Development of Guidelines for Quantifying Benefits of Traffic Incident Management Strategies (2022) / Chapter Skim
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6 REVIEW OF TIM DEFINITIONS, STRATEGIES, AND EVALUATION METHODS The first activity in support of NCHRP 03-108 is reviewing existing TIM evaluation methods, and cataloging frequently used definitions, classifications, and parameters employed in evaluations. This review effort documents operational efficiencies gained through the coordinated activities among partners within a TIM program and catalogs performance measure definitions, methods, and assumptions found in TIM literature.
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7 attention. Significant literature highlights best practices for TIM activities, including the TIM Handbook (Owens, 2010)
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8 program resources and funding methods for measuring progress Examples of the partnerships, multidisciplinary team training, and TIM progress abound. The Delaware Valley Regional Planning Commission Incident Management Task Force (IMTF)
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9 formalized through operational agreements, joint operational polices, and joint training exercises. The most commonly cited areas of multi-agency coordination in the literature were forming a defined team that regularly meets to discuss and plan for TIM activities and multi-agency training and exercises.
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10 "The Move Over, America" Campaign was the first coordinated national effort to educate Americans about "Move Over" laws and how they help protect the law enforcement officers who risk their lives protecting the public (http://www.moveoveramerica.com)
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11 Another exception is Georgia's Towing and Recovery Incentive Program (TRIP) which pays qualified heavy duty towing and recovery companies monetary bonuses for clearing large commercial vehicle incidents within 90 minutes.
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12 effectiveness of FSP as an incident management tools depends on several factors including incident frequency and characteristics, freeway operational characteristics and FSP implementation. The FSP benefits would be significant on freeway segments with narrow (or no)
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13 Tactical clearance and recovery activities include: Expedited Crash Investigation Service Patrols Vehicle-Mounted Push Bumpers Towing and Recovery Quick Clearance Incentives Major Incident Response Teams 2.1.3. Support TIM Activities Support TIM strategies include technology implementation and upgrades, data integration, and cost or recovery management.
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14 Florida Department of Transportation (FDOT) District 4 has deployed an Interagency Video Event Data Distribution System (iVEDDS)
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15 However, nearly all public agencies collect data on incident management for cost management purposes (Rensel, 2012)
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16 In 2013 National Cooperative Highway Research Program embarked upon developing guidelines for the implementation of TIM performance measures (Pecheux and Lomax, 2013) , focusing on principles of performance measurement.
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17 vehicles, spilled cargo, highway maintenance and reconstruction projects, and special nonemergency events." Conversely, the Manual on Uniform Traffic Control Devices (MUTCD) defines a traffic incident conservatively as an "emergency road user occurrence, a natural disaster, or other unplanned event that affects or impedes the normal flow of traffic." This definition precludes both maintenance and planned special events.
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18 characteristics such as time of day, geographical location, type of vehicles involved, or severity of injuries incurred." The number of incidents over a defined period of time can also quantify TMC workload. The incident count metric can capture the effects of specific TIM strategies.
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19 Location: left shoulder, divide, in-lane, and right shoulder Response: assisted, unassisted Assist Activity: mechanical/electrical, out of gas, flat tire, debris, accident, and other Incident Type. Incident type varies depending on the definition of traffic incidents.
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20 Agency/System or TIM Incident Type Source Washington DOT/Incident Response (IR) Teams Fatality collision, Injury collision, Non-injury collision, Abandoned vehicle, Disabled vehicle, Debris, Police activity, and Other Yinhai et al., 2011 Law enforcement and emergency response incident classifications focus on the number and severity of potential injuries and equipment required of the event.
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21 Some agencies go as far as to define incidents based on the level of response. Caltrans defines major incidents as "An unplanned non-recurring event that reduces highway capacity that requires both the California Highway Patrol and Caltrans to respond to the incident scene" (Chu, 2010)
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22 Kabengele in 1994 applied a broad temporal and spatial range–one hour after the primary accident and within three miles upstream of the primary accident– and noted anywhere from 5% to 14% of accidents are secondary. This range reflected years 1991 and 1992 on four Maryland facilities –US 50, I-95, I-495, and I-695.
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23 "Of all accidents, 7.5% had associated secondary incidents, 1.5% of disabled vehicles had secondary incidents, and 0.9% of abandoned vehicles had secondary incidents. The study also found that a 10-minute increase in primary incident duration is associated with 15% higher odds of secondary incidents." 2.2.3.
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24 by the University of Maryland (Chang and Raqib, 2013) , the evaluation of detection focuses on the distribution of detection sources.
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25 Health departments Conklin et al.
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26 2.2.6. Roadway Clearance Time Roadway clearance time is one of the three TIM program performance measures identified by FHWA.
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27 considered acceptable as a last responder. Recorded incident clearance metrics sometimes include the queue dissipation time.
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28 While assumed percentage of total incident is easiest to apply, it is also the coarsest in estimating true secondary incidents. Filtering provides a better estimate; however, the filter specification (temporal and spatial)
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29 examined in detail in each subsection below beginning with a summary table noting the TIM outcomes that are quantified and monetized. Section 5 of this document summarizes the federal direction for transforming outcomes to monetized benefits.
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30 𝐶 0.42 𝑓𝑜𝑟 𝑎𝑢𝑡𝑜𝑚𝑜𝑏𝑖𝑙𝑒𝑠1.87 𝑓𝑜𝑟 ℎ𝑒𝑎𝑣𝑦 𝑡𝑟𝑢𝑐𝑘𝑠 The change in vehicle miles traveled (VM) and change in congestion delay (CD)
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31 Next, the resulting time duration in queue with and without (baseline) TIM was calculated using the getaway capacity, reduced capacity and demand flow as inputs in the following equations: 𝑡 𝑡 𝜇 𝜇𝜇 𝜆 𝑡 𝑡 𝜇 𝜇𝜇 𝜆 Where: 𝑡 𝑡𝑖𝑚𝑒 𝑑𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑖𝑛 𝑞𝑢𝑒𝑢𝑒 𝑇𝐼𝑀 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 𝑡 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 𝑑𝑢𝑟𝑎𝑡𝑖𝑜𝑛,𝐹𝑖𝑒𝑙𝑑 𝑚𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑇𝐼𝑀 𝐼𝑛𝑐𝑖𝑑𝑒𝑛𝑡 𝜆 𝑑𝑒𝑚𝑎𝑛𝑑 𝑓𝑙𝑜𝑤 𝑡 𝑡𝑖𝑚𝑒 𝑑𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑖𝑛 𝑞𝑢𝑒𝑢𝑒 𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 𝑡 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 𝑑𝑢𝑟𝑎𝑡𝑖𝑜𝑛 𝑏𝑎𝑠𝑒𝑙𝑖𝑛𝑒 𝑖𝑛𝑐𝑖𝑑𝑒𝑛𝑡 It is worth noting that a separate calculation for time duration in queue was suggested for an incident with partial clearance occurring before complete clearance.
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32 2.3.3. Rutgers Incident Management System (RIMS)
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33 Table 8: Incident Management Assistance Patrols Decision-Support Tool for Service Expansion Estimation Framework Outcomes Outcome Estimated? Estimation Method Outcome Monetized?
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34 consist of North Carolina Department of Transportation (NCDOT) GIS shapefiles and NCDOT crash and inventory data.
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36 conditions. The impact area, shown in Figure 5, was defined by spatial and temporal impact boundaries estimated using regression models.
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37 Figure 6: Three Stage Time Savings Analysis for TIM (Chou, 2010)
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38 2.3.7. Methodology for Quantifying the Cost Effectiveness of Freeway Service Patrol Programs: Hudson Valley Highway Emergency Local Patrol Hagani et al.
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39 cost ratio analysis indicates that for segments which are similar to the study area, HELP program implementation was recommended only for volumes values greater than 1500 passenger cars per hour per lane (Level of Service C)
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40 Table 12: Assessing Return on Investment of Freeway Safety Service Patrol Programs Estimation Framework Outcomes Outcome Estimated? Estimation Method Outcome Monetized?
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41 2.3.9. A Benefit Cost Model for Traffic Incident Management, Knoxville, TN The study by Moss (2012)
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42 Next, the reduction in available capacity from the incident was used to calibrate the model so the measured delays could be plotted on the queuing diagram. To do so, a range of available capacity by lane blockage was suggested.
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43 nationwide survey of multiple incident management agencies. The study also evaluated the specific impact of traffic incident on both motorists and the environment on South Carolina freeways by using traffic simulation and benefit-cost analysis.
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44 Table 15: Evaluated Incident Clearance Strategies in Chowdhury et al.
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45 Table 16: Evaluation of Arterial Service Patrol Programs (I-64 Traffic Response) Estimation Framework Outcomes Outcome Estimated?
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46 Department of Natural Resources. Finally, $57,977 was saved by having the safety service patrol respond without having to call on police, highway employees, or others.
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47 at the time of incident such as volume and speed, and 3) response and clearance information of MA and non-MA scenario.
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48 the calculation of the benefit-cost ratio such as reductions in air pollutant emissions. In addition, the presence of Road Ranger service provides a sense of security on the freeway, and the quicker removal of incidents could reduce secondary accidents.
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49 Table 20: FIRST Benefits and Costs in 2003 Dollars (Mn/DOT, 2004)
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50 Analysis determined that CHART's services in 2012 reduced delays by 28.47 million vehiclehours. The incident-related traffic delay model is as follow: Sample Incident Delay = Traffic delay with an incident – traffic delay without an incident Incident Delay = f(incident duration, traffic volume, No.
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51 Table 22: Results of Service Patrol Benefit-Cost Studies (Lin, 2012) The Tool for Operations Benefit/Cost (TOPS-BC)
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52 Revised Departmental Guidance on Treatment of the Economic Value of a Statistical Life in U.S. Department of Transportation Analyses (2013)
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53 2.4.3. Crash Costs The U.S.
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54 Although these values do reflect the value of the driver's time, they do not reflect the total time value of the freight-hauling truck. In the passenger vehicle, the passengers are the valuable things being carried, and so we use their earning power to establish time value for the passenger vehicle.
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55 2.4.5. Occupancy Ratios As shown in the table below, the 2009 National Household Travel Survey (NHTS)
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56 2.4.8. Travel Time Reliability Value of reliability -- cost of unexpected delay -- is an important element of time cost, but there is no official guidance on this point.
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57 The next step of the project was to select specific methods that quantify and monetize TIM benefits for testing, using data sets from several regions within the U.S. The team developed broad TIM profiles for several state stakeholders and engaged each state to identify the range and time horizon of data for possible analysis.
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