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Cited by 37Fire effects on ecosystemsFacility Location and Emergency ManagementEvacuation and Crowd Dynamics

The DOI matches its Crossref record; 20 of the 20 references it cites were found in a registry or an index; 2 of the 29 sources its claims cite were checked for support.

Escape Route Index: A Spatially-Explicit Measure of Wildland Firefighter Egress Capacity

Open access
Campbell, Michael J., Page, Wesley G., Dennison, Philip E., Butler, Bret W.·2019·Fire
DOI 10.3390/fire2030040
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Abstract

For wildland firefighters, the ability to efficiently evacuate the fireline is limited by terrain, vegetation, and fire conditions. The impacts of terrain and vegetation on evacuation time to a safety zone may not be apparent when considering potential control locations either at the time of a wildfire or during pre-suppression planning. To address the need for a spatially-explicit measure of egress capacity, this paper introduces the Escape Route Index (ERI). Ranging from 0 to 1, ERI is a normalized ratio of the distance traveled within a time frame, accounting for impedance by slope and vegetation, to the optimal distance traveled in the absence of these impediments. An ERI approaching 1 indicates that terrain and vegetation conditions should have little impact on firefighter mobility while an ERI approaching 0 is representative of limited cross-country travel mobility. The directional nature of evacuation allows for the computation of four ERI metrics: (1) ERImean (average ERI in all travel directions); (2) ERImin (ERI in direction of lowest egress); (3) ERImax (ERI in direction of highest egress); and (4) ERIazimuth (azimuth of ERImax direction). We demonstrate the implementation of ERI for three different evacuation time frames (10, 20, and 30 min) on the Angeles National Forest in California, USA. A previously published, crowd-sourced relationship between slope and travel rate was used to account for terrain, while vegetation was accounted for by using land cover to adjust travel rates based on factors from the Wildland Fire Decision Support System (WFDSS). Land cover was found to have a stronger impact on ERI values than slope. We also modeled ERI values for several recent wildland firefighter entrapments to assess the degree to which landscape conditions may have contributed to these events, finding that ERI values were generally low from the crews’ evacuation starting points. We conclude that mapping ERI prior to engaging a fire could help inform overall firefighter risk for a given location and aid in identifying locations with greater egress capacity in which to focus wildland fire suppression, thus potentially reducing risk of entrapment. Continued improvements in accuracy of vegetation density mapping and increased availability of light detection and ranging (lidar) will greatly benefit future implementations of ERI.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

The paper introduces the Escape Route Index (ERI), a spatially explicit 0–1 measure of wildland firefighter egress capacity based on slope and land cover impedance. Applied across Angeles National Forest and 11 entrapment events, ERI shows land cover dominates over slope and that modeled egress was generally low at entrapment starting points.

Key findings

  • ERI is a suite of four metrics: ERI mean, ERI min, ERI max, and ERI azimuth; ERI max values are higher than ERI mean, which are higher than ERI min by formulation.
  • Across Angeles National Forest, 30-min simulations had mean ERI max = 0.58 (SD 0.20), ERI mean = 0.43 (SD 0.17), and ERI min = 0.23 (SD 0.14); land cover had 3–4× the influence of slope in variable importance analyses.
  • For 11 recent wildland firefighter entrapments, 30-min simulations from evacuation starting points had mean ERI min = 0.21, mean ERI max = 0.64, and mean ERI mean = 0.43; mean ERI values for burnovers with fatalities tended to be lower than near misses and burnovers without fatalities.
  • Longer evacuation time frames smoothed ERI values spatially, and ERI azimuth produced larger patches of similar evacuation direction, which the authors suggest may be more useful operationally.

Methods

  • ERI is calculated as the ratio of actual travel distance within a chosen time frame, accounting for slope and land cover impedance, to optimal travel distance in the absence of those impediments; it ranges from 0 to 1.
  • The study used 30-m DEM and LANDFIRE Existing Vegetation Type data, plus roads/trails, across Angeles National Forest; slope conductance came from Campbell et al.’s slope–travel rate function, and land cover conductance came from WFDSS factors.
  • Travel time was modeled cell-by-cell using Dijkstra’s algorithm via the `accCost` function in R’s `gdistance` library for 10-, 20-, and 30-min frames; 100 boundary points and eight travel directions were used, with ANOVA and relative importance analysis on 10,000 random points, plus ERI modeling for 11 entrapment events since 2001.

Limitations

  • The paper states ERI is not a real-time product and does not account for fire extent or growth trajectory, safety zones, situational awareness, or snag hazard; it assumes travel is restricted only by slope and land cover.
  • The paper notes entrapment analyses used pre-fire land cover, could not verify roads/trails temporal accuracy, omitted fire extent at evacuation time, and found ERI values generally low; WFDSS categorical land cover may misclassify traversability, as with the Yarnell/Granite Mountain case.
  • The text also makes evident that 30-m LANDFIRE data miss many smaller roads and trails, eight-direction raster travel is an approximation, and the optimal travel distance polygon is not perfectly circular.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3390/fire2030040

Cites

20 of 20 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Verification

Claims the paper makes

2 of 29 cited sources checked · 0 supported · 0 flagged · accuracy not yet measured

  • Findingown data

    ERI values were generally low from the crews' evacuation starting points for recent wildland firefighter entrapments.

    “finding that ERI values were generally low from the crews' evacuation starting points.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Land cover classes or fuel types represent typical or average vegetation and ground surface conditions within each class.
  • Findingown data

    Land cover has a stronger impact on ERI values than slope.

    “Land cover was found to have a stronger impact on ERI values than slope.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: Land cover classes or fuel types represent typical or average vegetation and ground surface conditions within each class.
  • Findingreasoning

    Spatially, ERImin, ERImax, and ERImean follow similar geographic patterns, with areas of high ERI in one metric tending to produce high ERI in another and vice versa.

    “Spatially, ERImin, ERImax, and ERImean all follow similar geographic patterns-areas of high ERI in one metric tended to produce high ERI in another and vice versa.”
    Quote in the paperNot a substantial claim
  • Findingown data

    For the 30-min evacuation simulations, the mean ERImin across all incidents was 0.21.

    “the mean ERImin across all incidents was 0.21”
    Quote in the paperNot a substantial claim
  • Findingreasoning

    Longer travel times tend to produce larger patches of area with similar evacuation direction in ERIazimuth values.

    “The smoothing is also particularly clear in the ERIazimuth values, such that longer travel times tend to produce larger patches of area with similar evacuation direction.”
    Quote in the paperNot a substantial claim
  • Probably not a substantial claim. 33
  • It may state two separate claims as one. 22

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Richmond et al. identify four parameters that affect the efficiency of pedestrian movement in a wildland environment: sinkage, slipperiness, roughness, and vegetation.

    “In a review of the energetic costs associated with traversing a diversity of landscape conditions, Richmond et al. [14] identify four parameters that affect the efficiency of pedestrian movement in a wildland environment: (1) sinkage (how deep a foot will sink into the ground surface);”
    Quote in the paperNot a substantial claim1 of 1 sources checked
    • cites Richmond et al. [14] Richmond, 2015, Terrain Factors for Predicting Walking and Load Carriage Energy Costs: Review and Refinement, J. Sport Hum. Perform. source

      The Abstract says that surface conditions affect the energy cost of walking and load carriage, supporting the general point about terrain and pedestrian movement. The passages retrieved for “sinkage,” “slipperiness,” “roughness,” and “vegetation” do not show Richmond et al. identifying those four parameters as a set. (LLM, conf=0.78)

      Experimental — accuracy not yet measured

  • It may state two separate claims as one.

    Premisecitation

    ANF is a very fire-prone area, with a history of wildland firefighter entrapments.

    “ANF was chosen for three reasons: (1) to demonstrate model implementation on a practical spatial scale; (2) it features a high diversity of both terrain and land cover conditions; and (3) it is a very fire-prone area, with a history of wildland firefighter entrapments [22].”
    Quote in the paperSubstantial claim1 of 1 sources checked
    • cites [22] Page, W., Freeborn, P., Butler, B., and Jolly, W. (2019). A review of US wildland firefighter entrapments: trends, important environmental factors and research needs. Int. J. Wildland Fire. source

      The All entrapment trends section (page unavailable) reports a substantial history of firefighter entrapments in Southern California. It does not identify ANF or establish that ANF itself has had entrapments or is very fire-prone (searched: ANF, Angeles, and fire-prone area). (LLM, conf=0.78)

      Experimental — accuracy not yet measured

  • Probably not a substantial claim. It may state two separate claims as one.

    Findingnone given

    ERI output maps either provide a relative safety index, ranging from 0 to 1, or a suggested travel direction.

    “The output maps either provide a relative safety index, ranging from 0 to 1, or a suggested travel direction.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Findingreasoning

    By virtue of their formulations, ERImax values are higher than ERImean values, which are higher than ERImin values.

    “By virtue of their formulations, ERImax values are higher than ERImean values which are higher than ERImin values.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper may give no reason why it holds.

    Findingnone given

    The metric relies on US nationwide, publicly-available datasets.

    “Given that the metric relies on US nationwide, publicly-available datasets, the goal is that ERI metrics would be mapped in advance of fire suppression and used to direct fire crews toward potential control locations with higher capacity for evacuation, thus reducing the potential for injurious or even fatal entrapments.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim.

    Findingreasoning

    ERI does not map escape routes, per se; it highlights areas that have a greater or lesser capacity for providing efficient escape routes.

    “ERI does not map escape routes, per se, it highlights areas that have a greater or lesser capacity for providing efficient escape routes.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim.

    Findingnone given

    ERI is not a single metric, but a suite of four spatially-explicit metrics that define the relative travel impedance caused by terrain and land cover faced by a fire crew, should that fire crew need to evacuate.

    “ERI is not a single metric, but a suite of four spatially-explicit metrics that define the relative travel impedance caused by terrain and land cover faced by a fire crew, should that fire crew need to evacuate.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim.

    Findingnone given

    In this paper, we have introduced a new metric for assessing and mapping egress capacity on a broad, spatial scale based on existing landscape conditions.

    “In this paper, we have introduced a new metric for assessing and mapping egress capacity, or the degree to which one can evacuate from a given location, on a broad, spatial scale based on existing landscape conditions.”
    Quote in the paperSubstantial claim

  • It may state two separate claims as one.

    Findingown data

    The 11 wildland firefighter entrapment events show a diversity of landscape conditions, with some featuring comparably favorable conditions (Holloway, Yarnell, King, Preacher) and others comparably unfavorable conditions (Cramer, Little Venus, Horseshoe 2, Horse Park).

    “The results highlight a diversity of landscape conditions faced by firefighters among these events, with some featuring comparably favorable landscape conditions (e.g., Holloway (Figure 11e), Yarnell (Figure 11f), King (Figure 11g), and Preacher (Figure 11i)), and others featuring comparably unfavorable conditions (e.g., Cramer (Figure 11a), Little Venus (Figure 11b), Horseshoe 2 (Figure 11d), and”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingreasoning

    ERI maps provide a map of relative egress capacity from anywhere in a wildland environment, regardless of proximity to a hospital, focused more on evacuation from the fireline to a safety zone than to a health care facility.

    “ERI maps, on the other hand, provide fire managers with a map of relative egress capacity from anywhere in a wildland environment, regardless of proximity to a hospital, and are thusly focused more on evacuation from the fireline to a safety zone than to a health care facility.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: WFDSS evacuation maps provide a map of estimated time to evacuate to the nearest hospital, taking into account distance to hospitals and automotive travel along a road network.

  • It may state two separate claims as one.

    Findingown data

    Although some mapped travel distances are larger than others, the ERI values across the board are still quite low.

    “(4) although some of the travel distances mapped are larger than others, and as such suggest greater egress capacity, the ERI values across the board are still quite low (Figure 12).”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    The starting point of the escape route that the Granite Mountain Hotshots took possessed a relatively high ERI value, even though their evacuation resulted in one of the most significant fatality events in the history of wildland firefighting.

    “For example, our evaluation highlighted the fact that the starting point of the escape route that the Granite Mountain Hotshots took possessed a relatively high ERI value, even though their evacuation resulted in one the most significant fatality events in the history of wildland firefighting.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Findingnone given

    A more precise slope-travel rate function is used as a basis of travel impedance in ERI.

    “Additionally, a more precise slope-travel rate function is used as a basis of travel impedance.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Findingown data

    ERI demonstrates a strong influence from land cover, much greater than slope, and the WFDSS-based land cover effects are very dominant.

    “In its current formulation, based on its current input parameters and datasets, ERI clearly demonstrates a strong influence from land cover-a much greater influence than that of slope.”
    • Also stated in: § 4. Discussion · boosted
      “While a previous study has likewise concluded that land cover (in particular, the density of vegetation) can have a stronger effect than slope on travel rates [8], the magnitude of the relative land cover effects derived from WFDSS in this study are very dominant (Figure 10; Table 8).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [8] Campbell, 2017, A LiDAR-based analysis of the effects of slope, vegetation density, and ground surface roughness on travel rates for wildland firefighter escape route mapping, Int. J. Wildland Fire source
    • cites Figure 10

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Table 8

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim. It may be too vague to check against evidence. It may state two separate claims as one.

    Interpretationreasoning

    Mapping ERI prior to engaging a fire could help inform overall firefighter risk for a given location and aid in identifying locations with greater egress capacity in which to focus wildland fire suppression, thus potentially reducing risk of entrapment.

    “We conclude that mapping ERI prior to engaging a fire could help inform overall firefighter risk for a given location and aid in identifying locations with greater egress capacity in which to focus wildland fire suppression, thus potentially reducing risk of entrapment.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: Land cover classes or fuel types represent typical or average vegetation and ground surface conditions within each class.

  • Probably not a substantial claim.

    Interpretationreasoning

    ERI azimuth tells a fire crew which direction, generally, to take.

    “ERI azimuth tells that same fire crew which direction, generally, to take.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. It may be too vague to check against evidence. The paper may give no reason why it holds.

    Interpretationnone given

    ERI mean is the best representation of the overall egress capacity for a given location.

    “It is the best representation of the overall egress capacity for a given location.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Premisecitation

    Alexander et al. found that open fuel types tend to promote the fastest travel, whereas lodgepole pine stands increase travel time by a factor of about 1.3, and dense spruce and fir forests increased travel time by a factor of about 1.8.

    “The results show that open fuel types, such as grasslands and logging slash tend to promote the fastest travel, whereas lodgepole pine stands with an open understory increase travel time by a factor of about 1.3, and dense spruce and fir forests increased travel time by a factor of about 1.8.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Alexander et al. [17]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim.

    Interpretationreasoning

    ERI min provides fire personnel with a sense of the worst-case evacuation scenario based on existing landscape conditions.

    “ERI min provides fire personnel with a sense of the worst-case evacuation scenario based on existing landscape conditions.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper may give no reason why it holds.

    Interpretationnone given

    An additional benefit to focusing on external factors is that most external factors can be mapped on a broad spatial scale using a combination of remote sensing and GIS.

    “An additional benefit to focusing on external factors is that most external factors can be mapped on a broad spatial scale using a combination of remote sensing and geographic information systems (GIS).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. It may state two separate claims as one.

    Premisecitation

    According to the Yarnell Hill Serious Accident Investigation Report, the dominant vegetation type, chaparral brush, ranged in height from one to ten feet and, in some places, was nearly impenetrable.

    “However, according to the Yarnell Hill Serious Accident Investigation Report,”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [33] Arizona State Forestry Division (2019, July 07). Available online: https://wildfiretoday.com/documents/Yarnell_Hill_Fire_report.pdf.

  • Probably not a substantial claim. It may state two separate claims as one.

    Interpretationreasoning

    To be useful for wildland firefighters, escape route mapping has to be done in real-time or near-real-time, which requires the location of the crew, the location of the designated safety zone, and the extent and predicted spread of the fire.

    “Thus, to be useful for wildland firefighters, escape route mapping has to be done in real-time or near-real-time, which requires three things: (1) the location of the crew; (2) the location of the designated safety zone; and (3) the extent and predicted spread of the fire.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Interpretationreasoning

    ERI and a terrain-driven viewshed analysis would likely be highly correlated.

    “It is likely that ERI and a terrain-driven viewshed analysis would be highly correlated, since, for example a narrow canyon with limited visibility would also have low egress capacity and vice versa.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Interpretationreasoning

    The same land cover travel impedance coefficients are used in both WFDSS evacuation maps and ERI, but the end goals of the two products are distinct.

    “Although the same land cover travel impedance coefficients are used in both, the end goals of the two products are distinct.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: WFDSS evacuation maps provide a map of estimated time to evacuate to the nearest hospital, taking into account distance to hospitals and automotive travel along a road network.
    • Rests on an assumption: Relatively coarse slope categories are used to model travel impedance in WFDSS evacuation maps.
    • Rests on an assumption: The WFDSS evacuation map product is a map of absolute travel time.

  • Probably not a substantial claim.

    Interpretationreasoning

    A high ERI max value tells a fire crew that there is at least one direction by which pedestrian evacuation travel efficiency will be very high.

    “A high ERI max value tells a fire crew that there is at least one direction by which pedestrian evacuation travel efficiency will be very high.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    WFDSS uses land cover factors to adjust travel rates for its Ground Medevac Time dataset.

    “The Wildland Fire Decision Support System (WFDSS) uses land cover factors to adjust travel rates for its Ground Medevac Time dataset (Table 2).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [18] (2019, May 28). Wildland Fire Decision Support System WFDSS Help | Estimated Ground Medevac Time, Available online: https://wfdss.usgs.gov/wfdss_help/WFDSSHelp_Est_Grd_Medevac_Time.html.

  • Probably not a substantial claim. The paper may give no reason why it holds.

    Interpretationnone given

    High ERI mean values are likely to produce desirable evacuation conditions.

    “High ERI mean values are likely to produce desirable evacuation conditions.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. It may state two separate claims as one.

    Study design and conductcitation

    Travel was restricted to directionally-specific slopes within ±30° to avoid extrapolation of the Campbell et al. travel rate function and to avoid modeling travel up or down very steep slopes.

    “For the purpose of this study, to avoid extrapolation of the Campbell et al. [11] travel rate function and to avoid modeling travel up or down very steep slopes, travel was restricted to directionally-specific slopes within ±30 • .”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Campbell et al. [11] Campbell, 2019, Using crowdsourced fitness tracker data to model the relationship between slope and travel rates, Appl. Geogr. source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Interpretationreasoning

    Other important safety factors not directly incorporated into ERI are situational awareness and potential for snag hazard.

    “Other important safety factors not directly incorporated into ERI are: (1) situational awareness; and (2) potential for snag hazard.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it.

    Interpretationreasoning

    Given the sparseness of experimental data on the effects of land cover on travel rates, it is unclear which among the few studies have produced the most reliable results.

    “Given the sparseness of experimental data on the effects of land cover on travel rates, it is unclear which among the few studies, have produced the most reliable results.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Premisecitation

    The 10, 20, and 30 min time frames reflect reasonable travel times from the fireline to a safety zone according to historical wildland firefighter entrapments, while balancing computational cost.

    “These times were chosen to reflect reasonable travel times from the fireline to a safety zone, according to historical, well-documented wildland firefighter entrapments [23], while balancing the computational cost associated with processing longer travel times.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [23] (2019, June 06). Escape Routes 1 (Take 5@2) | NWCG, Available online: https://www.nwcg.gov/committee/6mfs/escape-routes1.

  • Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it.

    Premisecitation

    Safety is but one component of the complex, multifaceted wildland fire decision making process.

    “Although critical, safety is but one component of the complex, multifaceted wildland fire decision making process [30].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [30] Thompson, 2017, A review of challenges to determining and demonstrating efficiency of large fire management, Int. J. Wildland Fire source

      Checked before — its earlier verdict is held back until a new check runs.

  • It may state two separate claims as one.

    Interpretationreasoning

    ERI is not a real-time product, as it does not reflect real-time conditions, making it a pre-fire decision support tool.

    “Thus, ERI is not a real-time product, as it does not reflect real-time conditions making it a pre-fire decision support tool.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: ERI assumes that travel is not restricted in any direction by any factors other than slope and land cover.
    • Rests on an assumption: In reality, fire crews may have 50% or more of potential evacuation directions cut off by the fire itself.

  • Probably not a substantial claim. It may state two separate claims as one.

    Premisereasoning

    WFDSS was chosen in this study due to its reliance on existing nationwide data and its wide use in the wildland fire community.

    “WFDSS was chosen in this study due to its reliance on existing nationwide data and its wide use in the wildland fire community, but future research may reveal different, more accurate land cover conductance values that should be incorporated into future iterations of ERI.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Safety zones are often designated 'in the black'-in areas that have already burned.

    “However, safety zones are often designated”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [28] (2019, June 07). Safety Zones 1 (LCES) | NWCG, Available online: https://www.nwcg.gov/committee/6mfs/safety-zones1-lces.

  • Probably not a substantial claim. It may be too vague to check against evidence. The paper’s conclusions may not depend on it. The paper may give no reason why it holds.

    Interpretationnone given

    To more accurately simulate movement in a wildland environment, the effects of land cover on travel rates also need to be taken into account.

    “However, to more accurately simulate movement in a wildland environment, the effects of land cover on travel rates also need to be taken into account.”
    Quote in the paperNot a substantial claim

  • It may state two separate claims as one.

    Interpretationnone given

    Internal factors are highly variable within a population, but if a fire crew moves as a unit, then they are only as fast as the slowest individual in the group.

    “Internal factors are highly variable within a population, but if a fire crew moves as a unit, then they are only as fast as the slowest individual in the group.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Study design and conductnone given

    It is impossible to determine on a case-by-case basis the temporal accuracy of the roads and trails used in the ERI modeling.

    “(2) it is impossible to determine on a case-by-case scenario the temporal accuracy of the roads and trails-some may have existed pre-fire, but some may have been developed during or after the fire;”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. It may be too vague to check against evidence. It may state two separate claims as one.

    Premisenone given

    Means are simply a measure of central tendency, and do not reflect the directionally-specific evacuation conditions.

    “However, means are simply a measure of central tendency, and do not reflect the directionally-specific evacuation conditions.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim. The paper may give no reason why it holds.

    Interpretationreasoning

    When mapped in advance of a wildland fire, the ERI can help wildland firefighters identify potential control locations in areas with favorable conditions for evacuation.

    “When mapped in advance of a wildland fire, the ERI can help wildland firefighters identify potential control locations in areas with favorable conditions for evacuation.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim.

    Interpretationcitation

    By combining the slope-travel rate function defined by Campbell et al. and the land cover-travel rate effects defined by WFDSS, spatially-explicit escape route mapping could become a reality.

    “By combining the slope-travel rate function defined by Campbell et al. [11], and the land cover-travel rate effects defined by WFDSS [18], spatially-explicit escape route mapping could become a reality.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Campbell et al. [11] Campbell, 2019, Using crowdsourced fitness tracker data to model the relationship between slope and travel rates, Appl. Geogr. source
    • cites WFDSS [18]

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim. The paper’s conclusions may not depend on it.

    Premisecitation

    Campbell et al. used airborne lidar remote sensing to derive continuous measures of slope, vegetation density, and ground surface roughness as the basis of travel impedance analysis.

    “Campbell et al. [8] used airborne lidar remote sensing to derive continuous measures of slope, vegetation density, and ground surface roughness as the basis of travel impedance analysis.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Campbell et al. [8] Campbell, 2017, A LiDAR-based analysis of the effects of slope, vegetation density, and ground surface roughness on travel rates for wildland firefighter escape route mapping, Int. J. Wildland Fire source

  • It may state two separate claims as one.

    Interpretationreasoning

    Areas with low ERI values possess some combination of rugged terrain and dense vegetation, thus making the designation of suitable escape routes difficult or even impossible.

    “Conversely, areas with low ERI values possess some combination of rugged terrain and dense vegetation, thus making the designation of suitable escape routes difficult or even impossible.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim.

    Premisecitation

    Understory vegetation density is thought to be a much better predictor of travel conductance.

    “which is thought to be a much better predictor of travel conductance [8,34].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [8] Campbell, 2017, A LiDAR-based analysis of the effects of slope, vegetation density, and ground surface roughness on travel rates for wildland firefighter escape route mapping, Int. J. Wildland Fire source
    • cites [34] Campbell, 2018, Quantifying understory vegetation density using small-footprint airborne lidar, Remote Sens. Environ. source

  • Probably not a substantial claim. The paper’s conclusions may not depend on it. It may state two separate claims as one.

    Premisecitation

    The effects of slope on travel rates have been studied since the nineteenth century, and several models for predicting travel rates based on slope have been developed, including Naismith's Rule and Tobler's Hiking Function.

    “The effects of slope on travel rates have been studied since the nineteenth century, and several models for predicting travel rates based on slope have been developed, including the widely-used Naismith's Rule and Tobler's Hiking Function [9,10].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [9] Naismith, 1892, Cruach Adran, Stobinian, and Ben More, Scott. Mt. Club J.

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [10] Tobler, W. (1993). Three Presentations on Geographical Analysis and Modeling, National Center for Geographic Information and Analysis.
45 of 45

  • The authors state this as an assumption.

    Land cover classes or fuel types represent typical or average vegetation and ground surface conditions within each class.

    “Absent direct quantification of ground surface condition and vegetation, land cover or fuel type can serve as a proxy, assuming that land cover classes or fuel types represent typical or average vegetation and ground surface conditions within each class.”

  • The paper relies on this without support.

    Both T1 and T2 are difficult to predict accurately in the field.

    “Both T1 and T2 are difficult to predict accurately in the field.”

  • The paper relies on this without support.

    Considerably less attention has been devoted to predicting T2 than to predicting T1.

    “Considerably less attention has been devoted to predicting T2, which is controlled by a combination of internal factors (e.g., height, weight, fitness and endurance levels, and load carriage) and external factors (e.g., landscape and environmental conditions).”

  • The paper relies on this without support.

    The effects of ground surface condition and vegetation are both less well-understood and more difficult to map.

    “The effects of ground surface condition and vegetation are both less well-understood and more difficult to map.”

  • The authors state this as an assumption.

    ERI assumes that travel is not restricted in any direction by any factors other than slope and land cover.

    “ERI makes the naïve assumption that travel is not restricted in any direction by any factors other than slope and land cover.”

  • The paper relies on this without support.

    In reality, fire crews may have 50% or more of potential evacuation directions cut off by the fire itself.

    “In reality, fire crews may have 50% or more of potential evacuation directions cut off by the fire itself.”

  • The paper relies on this without support.

    LCES is an integrated system of four inherently interdependent safety measures, not a sequence of four disparate safety measures.

    “LCES is not a sequence of four disparate safety measures, it is an integrated system of four inherently interdependent safety measures.”

  • The paper relies on this without support.

    If no suitable safety zone is accessible from the fireline, then no escape route, regardless of how efficient, is going to be of value.

    “If no suitable safety zone is accessible from the fireline, then no escape route, regardless of how efficient, is going to be of value.”

  • The paper relies on this without support.

    WFDSS evacuation maps provide a map of estimated time to evacuate to the nearest hospital, taking into account distance to hospitals and automotive travel along a road network.

    “WFDSS evacuation maps provide fire managers with a map of the estimated time it would take someone to evacuate to the nearest hospital, and as such, necessarily takes into account the distance to hospitals and automotive travel along a road network.”

  • The paper relies on this without support.

    Relatively coarse slope categories are used to model travel impedance in WFDSS evacuation maps.

    “In addition, relatively coarse slope categories are used to model travel impedance.”

  • The paper relies on this without support.

    The WFDSS evacuation map product is a map of absolute travel time.

    “The resulting product is a map of absolute travel time.”

  • The paper relies on this without support.

    Land cover datasets are predominantly derived from passive remote sensing instruments that record reflected solar radiation from the uppermost portions of the Earth's surface, such as Landsat, and they lack the ability to precisely model vertical structure of the landscape.

    “Because land cover datasets are predominantly derived from passive remote sensing instruments that record reflected solar radiation from the uppermost portions of the Earth's surface, such as Landsat, they lack the ability to precisely model vertical structure of the landscape.”

  • The paper relies on this without support.

    Active instruments, such as lidar, are capable of making precise x, y, and z measurements, and exploiting small gaps in a vegetated canopy to make measurements of understory vegetation density.

    “However, active instruments, such as lidar, are capable of making precise x, y, and z measurements, and exploiting small gaps in a vegetated canopy to make measurements of understory vegetation density, which is thought to be a much better predictor of travel conductance [8,34].”
13 of 13

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Improving our understanding of how firefighters traverse various landscapes is essential for the assessment of relative egress capacity, estimation of medical evacuation time, mapping of least-cost escape routes, and knowledge of when to trigger an evacuation.

    “Improving our understanding of how firefighters traverse various landscapes is essential for the assessment of relative egress capacity [24], estimation of medical evacuation time [44], mapping of least-cost escape routes [34], and knowledge of when to trigger an evacuation [26].”

    From Modeling wildland firefighter travel rates by terrain slope: results from GPS-tracking of type 1 crew movement (2020) · cites this paper as [24]

  • Campbell et al.'s slope-travel rate function was used as the basis of predicting egress in the Escape Route Index.

    “Campbell et al. [29]'s slope-travel rate function was used as the basis of predicting egress in the Escape Route Index [24].”

    From Modeling wildland firefighter travel rates by terrain slope: results from GPS-tracking of type 1 crew movement (2020) · cites this paper as [24]

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Dijkstra citation points to an escape-routes source

    Minor

    The text cites reference 24 for Dijkstra's algorithm, but reference 24 is an NWCG escape-routes page. The Dijkstra paper is listed as reference 25.

  • Table 8 caption misidentifies its contents

    Minor

    The caption calls Table 8 descriptive statistics of ERI raster-cell values, but its columns report regression R2 and the relative importance of slope and land cover.

2 of 2

Citations

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. Beighley, 1995, Beyond the safety zone: Creating a margin of safety, Fire Manag. Notes, 55, 21
  2. Naismith, 1892, Cruach Adran, Stobinian, and Ben More, Scott. Mt. Club J., 2, 136

Cited by

Sorted by citations

Related

Metadata

Authors
Campbell, M. J., Page, W. G., Dennison, P. E., & Butler, B. W.
Affiliations
  • Fort Lewis College (US)
  • Rocky Mountain Research Station, USDA Forest Service, Missoula, MT 59808, USA
  • Department of Geography, University of Utah, Salt Lake City, UT 84112, USA
Corresponding author
Campbell, Michael J.
ORCID
Venue
Fire
Publisher
MDPI AG
Published
2019-07-08
Volume
2
Issue
3
Pages
40
ISSN
2571-6255 (ISSN-L)
DOI
10.3390/fire2030040
OpenAlex
W2961715102
Cited by
37
References
19
Citations by year
2026: 2 · 2025: 9 · 2024: 5 · 2023: 4 · 2022: 9 · 2021: 2 · 2020: 5 · 2019: 1
FWCI
1.67
Type
journal article
Language
en
Open access
Licence
Locations
  • Fire (publishedVersion, cc-by)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
U.S. Forest Service (18JV11221637154)
Topics
  • Physical Sciences › Environmental Science › Global and Planetary Change › Fire effects on ecosystems
  • Social Sciences › Decision Sciences › Management Science and Operations Research › Facility Location and Emergency Management
  • Social Sciences › Safety Research › Evacuation and Crowd Dynamics
Keywords
vegetation density, land cover, travel time modeling, Angeles National Forest

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