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    <title>Transport Research International Documentation (TRID)</title>
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    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
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    <item>
      <title>Evaluation of the Deployment of Arterial Service Patrol Program in Central Florida (Part 2)</title>
      <link>https://trid.trb.org/View/2448902</link>
      <description><![CDATA[The objective of this study is to evaluate the 1-year deployment of the arterial safety patrol program. Insights from this evaluation study will inform the possible extension of the program with modifications. In addition, the evaluation will also provide insights on enhancing the data and methodology used in the previous study for identifying priority locations for service deployment. This project is a continuation of research that began under BED31 TWO 977-16.]]></description>
      <pubDate>Tue, 05 Nov 2024 14:44:13 GMT</pubDate>
      <guid>https://trid.trb.org/View/2448902</guid>
    </item>
    <item>
      <title>Improving Effectiveness of the Safety Service Patrol Programs: A Discrete Event-Based Simulation Approach</title>
      <link>https://trid.trb.org/View/2382097</link>
      <description><![CDATA[Safety service patrols (SSPs) play an important role in incident management on highways. It is critical to respond to incidents in a timely manner as this can significantly reduce nonrecurrent congestion and improve safety. Therefore, it is essential to allocate available SSP vehicles to highway segments such that their effectiveness is maximized. This study aimed to develop a simulation-based framework to assist with SSP service optimization. More specifically, a discrete event-based simulation tool (i.e., SSP-OPT) with customizable parameters was developed to help plan the optimum patrol routes based on available SSP resources and predicted incidents. The developed tool was tested with roadway traffic and incident data from the Virginia highway network. After model calibration, the simulation results showed that the developed SSP-OPT tool could replicate the patrol routes with similar performance to the field observations, validating the tool. Further, adopting the tool for corridor-level optimization could help to identify the best patrol plan to minimize SSP response time and maximize SSP response rates for a given number of SSP vehicles. The SSP-OPT tool requires minimal user input (e.g., segment lengths, annual average daily traffic) and has the flexibility to be easily applied to any highway corridor once calibrated. The tool generates various performance metrics to enable more informed decision making in SSP route planning.]]></description>
      <pubDate>Mon, 27 May 2024 10:10:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/2382097</guid>
    </item>
    <item>
      <title>Development of Guidelines for Vehicle and Equipment Marking and Lighting</title>
      <link>https://trid.trb.org/View/2325959</link>
      <description><![CDATA[This report presents proposed guidelines for vehicle and equipment color, marking, and lighting practices. Static and dynamic tests were conducted to measure the effects of alternative vehicle marking and warning light treatments on driver perception of workers on foot and of moving work vehicles fitted with the treatments. Testing was also conducted to measure the effects of the alternative treatments on driver lane choice and speed. These guidelines will particularly benefit state department of transportation (DOT) operations personnel by more effectively identifying and communicating their presence to nearby motorists.]]></description>
      <pubDate>Thu, 25 Jan 2024 13:11:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/2325959</guid>
    </item>
    <item>
      <title>Improving Safety Service Patrol Performance</title>
      <link>https://trid.trb.org/View/2244226</link>
      <description><![CDATA[Safety Service Patrols (SSPs) provide motorists with assistance free of charge on most freeways and some key primary roads in Virginia. This research project is focused on developing a tool to help the Virginia Department of Transportation (VDOT) optimize SSP routes and schedules (hereafter called SSP-OPT). The computational tool, SSP-OPT, takes readily available data (e.g., corridor and segment lengths, turnaround points, average annual daily traffic) and outputs potential SSP configurations that meet the desired criteria and produce the best possible performance metrics for a given corridor. At a high level, the main components of the developed tool include capabilities to: a) generate alternative feasible SSP beat configurations for a corridor; b) predict incidents and SSP characteristics (e.g., incident frequency, SSP service time) for a given SSP beat configuration; c) estimate performance measures (e.g., SSP response time, number of incidents responded to); and d) identify and present the best SSP configuration(s) through visual aids that facilitate decision making. To generate the incident data needed for the simulation-based SSP-OPT tool, a hierarchical negative binomial model and a hierarchical Weibull model are developed for incident frequencies and incident durations, respectively, based on the historical incident data. These models have been found to be effective in simulating the spatiotemporal distribution of incidents along highway corridors and for generating their attribute data (e.g., incident type, duration). The simulation program employs a discrete event-based approach and requires a few calibration parameters (e.g., SSP vehicle speed). After calibrating the model, the validation results show good agreement with field observations when applied to a sample SSP corridor from I-95. A user interface is created for the SSP-OPT tool in MS Excel to facilitate data entry and visualization of the output metrics for a given corridor. The output includes the list of alternative feasible beat configurations and aggregated performance measures from multiple runs for each individual beat, as well as for each alternative beat configuration spanning the entire corridor. The proposed SSP optimization model could be applied to corridors with or without existing SSP service. The tool will help identify the best beat configurations to minimize SSP response times and maximize SSP response rates for a given number of SSP vehicles on a corridor. Implementing these optimal solutions in the field will result in travel time savings and improve highway safety since the SSP resources will be more efficiently utilized, thus reducing the impacts of incidents on traffic flow.]]></description>
      <pubDate>Tue, 19 Sep 2023 16:16:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2244226</guid>
    </item>
    <item>
      <title>Quantify Freeway Safety Service Patrol and Protect the Queue Impact on Transportation Network 
Reliability</title>
      <link>https://trid.trb.org/View/2142138</link>
      <description><![CDATA[The objective of this project is to evaluate and quantify the impacts and benefits of Freeway Safety Service Patrol (FSSP) and Protect the Queue (PTQ) programs using data-driven analysis. Tennessee Department of Transportation (TDOT)’s Locate/IM and PTQ daily working reports data are the primary source of this study, which will help better understand the characteristics of incidents. WAZE’s crowd-sourced incident report logs will be also heavily used in this project for the purpose of affording TDOT the flexibility of analyzing incidents outside the coverage areas by Locate/IM. The study reviewed the state-of-the-practice of traffic incident management (TIM) programs’ impact evaluation methodologies and end-of-queue crash risk probability estimation methods, evaluated the benefits of HELP program in three different aggregation levels and assessed the benefits of PTQ based on a risk probability model. The study also developed an automated workflow for generating benefit cost analysis for HELP and PTQ programs and provided an Excel-based automation tool for easy implementation. All reports and deliverables are ready to use with TDOT data. The procedures assess benefits resultant from savings in travel delay, emission, fuel consumption, and secondary crash for a wide range of programs. Results from this study will be readily implementable for the entire State, any region, or even individual counties. The deliverables of this project provide factual statistics backed by sound analysis to assist TDOT’S decision making process. The B/C reports for HELP program, for PTQ program, and for a new rural HELP program helps TDOT make important investment decisions to best serve the motoring public. The automated B/C reports for HELP program fulfills the recurring comprehensive performance monitoring objective. Furthermore, the incorporation of crowdsourced WAZE data into TDOT’s exiting traffic incident management data framework leads to better understanding of incident characteristics and more efficient incident management.]]></description>
      <pubDate>Tue, 28 Mar 2023 09:56:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/2142138</guid>
    </item>
    <item>
      <title>Corridor-Wide Surveillance Using Unmanned Aircraft Systems Phase II: Freeway Incident Detection using Unmanned Aircraft Systems Part B
</title>
      <link>https://trid.trb.org/View/2120992</link>
      <description><![CDATA[Unmanned aerial vehicles (UAVs) provide a platform that can carry cameras and sensors for collecting real-time traffic information, especially for corridors under congested conditions, when the traditional loop detectors do not work properly and where there is a lack of other means of traffic monitoring. As an alternative, Road Rangers continuously patrol the roadways monitoring for traffic crashes and stranded motorists and then respond to those incidents. Continuously patrolling along the roadways is costly and man-power consuming. In this study, the researchers will explore the possibilities of replacing the patrolling tasks of Road Rangers with UAVs. The challenging research problems include: (1) development of on-line incident detection methodology with video data from multiple flying UAVs; (2) UAV path planning for corridor incident detection; (3) design and conduct experiments aimed at establishing protocols, standards, and guidance for safely using multiple UAVs for monitoring corridor-wide traffic conditions to complement Part 107 of FAA regulations, as amended. This research requires three phases. Phase I focused on design and test of the operations of multiple UAVs for collecting traffic information and development of incident detection methodology (see NICR Project 4-3: Corridor-Wide Surveillance Using Unmanned Aircraft Systems). Phase II will involve two separate but related research efforts by University of Puerto Rico, Mayaguez (Part A) and The University of South Florida (Part B). The University of South Florida research team will conduct experiments along I-75 and I-275 freeway corridors in Tampa, Florida to verify the protocols, standards and guidance, as well as the methodologies developed in Phase I. In Phase III of this project, the research team will focus on the validation of the algorithms developed in the previous phases and implementation matters of Phase II.

]]></description>
      <pubDate>Tue, 21 Feb 2023 14:30:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/2120992</guid>
    </item>
    <item>
      <title>Case Study: Ohio Department of Transportation Freeway Safety Patrol Naming Rights Program</title>
      <link>https://trid.trb.org/View/2018817</link>
      <description><![CDATA[The Ohio Department of Transportation (ODOT) found unconventional ways to raise money to offset transportation budget shortfalls, one of which was, in 2014, to enter into a naming rights agreement with State Farm Insurance. Under this agreement State Farm advertises on ODOT vans that patrol highways to assist motorists. This program will raise as much as $8.65 million over 10 years, covering most of the cost of the Freeway Safety Patrol operations.]]></description>
      <pubDate>Tue, 20 Sep 2022 14:33:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/2018817</guid>
    </item>
    <item>
      <title>Road Ranger Programs for Arterials</title>
      <link>https://trid.trb.org/View/2012464</link>
      <description><![CDATA[The intent of this project was to examine the spatiotemporal profile of incidents and suggest an initial plan for service patrol deployment for the arterials in Orlando. The study area was defined by the following boundaries: SR-434 in the north, US-17-92, I-4, US-441 in the east, SR-482 (Sand Lake Rd) in the south; and Kirkman Rd, John Young Pkwy and US-441 in the west. Based on a spatiotemporal analysis of crash frequencies and clearance times, the southern part of the study area was identified as the primary candidate for the service patrol program. Numerical simulations to evaluate performance of staged and centrally dispatched service program with one vehicle were undertaken. The results indicated the service vehicle could respond to over 70% of the crashes on an average and that the average clearance time per crash would be around 30-40 minutes. Overall, the service patrol program could result in a reduction of 36 to 45 minutes of clearance time on average per crash. The service vehicle would be occupied for about 3-4 hours/day/shift. It is anticipated that a staged and centrally dispatched service patrol program will be deployed as a pilot in the southern part of the study area. Patrolling-based operations may also be tested for a couple of weeks during the pilot implementation to see if there are any unanticipated benefits. The data collected from the deployment will be used to re-evaluate the program (approximately 18 months after deployment) to make suitable modifications and to make recommendations for the best approaches for deploying service patrols in other arterials in the state of Florida.]]></description>
      <pubDate>Tue, 30 Aug 2022 09:18:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/2012464</guid>
    </item>
    <item>
      <title>Using AlgoTraffic Data to Improve Traffic Incident Management</title>
      <link>https://trid.trb.org/View/2010039</link>
      <description><![CDATA[Over the past few years, the Alabama Department of Transportation has taken a transportation systems management and operations (TSMO) approach to manage intelligent transportation system (ITS) assets and monitor congestion across their road network. Regional Traffic Management Centers (RTMCs) have been established in four of the five regions to monitor data and information from a newly developed ALGO Traffic web interface. The ALGO Traffic platform provides real-time feeds for cameras, speed sensors, and other pieces of infrastructure. This platform and data are used by RTMC operators to monitor and log crashes and other various types of incidents (disabled vehicles, construction, queues, etc.). The goal of this paper is to measure and understand the impact of the Alabama Service and Assistance Patrol (ASAP) on incident clearance time. The objectives of this paper include (1) to pair and analyze TMC incident data with crash data, (2) estimate a duration model for incident clearance time, and (3) assess the factors that contribute to incident clearance time. This study uses a fully parametric hazard-based duration model to statistically analyze the factors that affect the incident clearance time. The novelty of this paper is the inclusion of additional ASAP coverage area information in the duration models. The contribution of this paper is to provide a better understanding of the factors that contribute to the incident clearance time and to provide a quantitative estimate of the impact of ASAP programs.]]></description>
      <pubDate>Tue, 23 Aug 2022 11:25:09 GMT</pubDate>
      <guid>https://trid.trb.org/View/2010039</guid>
    </item>
    <item>
      <title>Evaluating the Impact of Freeway Service Patrol on Incident Clearance Times: A Spatial Transferability Test</title>
      <link>https://trid.trb.org/View/2004727</link>
      <description><![CDATA[Freeway service patrol (FSPs) programs have been considered as an effective tool for traffic incident management in minimizing the adverse effects of traffic incidents. In this study, random parameters hazard-based duration modeling method was used to evaluate the impact of the newly implemented Alabama Service and Assistance Patrol (ASAP) program, using incident clearance time as a performance measure. It was determined that there is a statistically significant difference in the factors that influence incidents clearance times between incidents that occurred inside and outside the ASAP regions. A total of five variables (on-road, nighttime, peak hours, rain, and fire response present) were observed to have random effects along with ten fixed effects variables on incidents occurring inside the ASAP regions. On the other hand, incidents that occurred outside the ASAP regions were found to have three random effects variables (on-road, nighttime, and fire response present) and seven fixed effects variables. The estimation results indicate a significant association of incident clearance times to incident related variables such as involvement of CMVs, fatality, vehicle towing, seat belt indicated as involved, and on-road incidents that occurred both inside and outside the ASAP regions. The results also reveal that incident clearance times are influenced strongly by temporal variables (e.g., nighttime), traffic factors (e.g., AADT), and operational variables (e.g., fire response present) for incidents both inside and outside the ASAP area models. Overall, it was observed that the incident clearance times recorded in the regions where the ASAP program is in effect are significantly different. The findings of this study are expected to be useful for the state traffic incident management (TIM) agencies in developing and executing strategies to minimize incident clearance times. Ultimately, the study provides a data-driven evidence-based assessment of the ASAP program in the state.]]></description>
      <pubDate>Mon, 22 Aug 2022 16:14:04 GMT</pubDate>
      <guid>https://trid.trb.org/View/2004727</guid>
    </item>
    <item>
      <title>Safety Service Patrol Standardization and Management Practices</title>
      <link>https://trid.trb.org/View/1894844</link>
      <description><![CDATA[The primary objective of this Pooled Fund Study study will be to gain technical information related to Safety Service Patrol (SSP0 program management, standards associated with SSP response protocol and the implementation of traffic control, and references and guidance related to staffing, training, and resource allocations within SSP programs. The goals include: (1) Assemble best practices and lessons learned from existing programs; (2) Develop guidance documents based on lessons learned from existing programs; (3) Reference or create tools that will help agencies make informed program decisions such as route selection, staffing levels, and resource allocation.]]></description>
      <pubDate>Wed, 01 Dec 2021 17:13:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1894844</guid>
    </item>
    <item>
      <title>Patrol Route Planning for Incident Response Vehicles under Dispatching Station Scenarios</title>
      <link>https://trid.trb.org/View/1871529</link>
      <description><![CDATA[Traffic incidents affect highway safety, induce congestion, and have indirect economic costs. Effective incident management on busy roads is crucial for timely detection and clearing of incidents, and restoration of traffic capacity. To mitigate congestion, it is best to plan simultaneously for location of first respondents’ dispatching stations and design of patrol routes. The authors present a route planning method to enable patrolling vehicles’ quick response to incidents, using a mixed-integer nonlinear program minimizing the respondents’ patrolling travel cost, based on expected response time to incident locations. The authors have developed a column generation-based solution for best route selection under different station designs. To investigate the impact of dispatching station design on the routing cost, an integrated genetic algorithm framework with embedded continuous approximation approach is developed, reducing the complexity of location design and route planning. Numerical experiments are conducted to evaluate the algorithm’s performance. These models and solution techniques can be applied to network problems involving simultaneous choices in routing and facility location.]]></description>
      <pubDate>Wed, 29 Sep 2021 09:34:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1871529</guid>
    </item>
    <item>
      <title>Performance Measure Evaluation of UDOT’s Traffic Incident Management Program</title>
      <link>https://trid.trb.org/View/1856970</link>
      <description><![CDATA[In this research, performance measures of the Utah Department of Transportation (UDOT) Traffic Incident Management (TIM) program were analyzed. Performance measures were determined for responding Incident Management Teams (IMT) and Utah Highway Patrol (UHP) units at 168 crashes. Statistical analyses were conducted to understand how the existing IMT program was performing. Results of statistical analyses showed that the effect of IMT response time (RT) on roadway clearance time (RCT) was statistically significant, while RT was not significant on incident clearance time (ICT) at the 95% confidence level. On average, for each minute delay of IMT response time, 0.8 min is added to the RCT ranging from 0.1 to 1.4 min.]]></description>
      <pubDate>Fri, 23 Jul 2021 15:26:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1856970</guid>
    </item>
    <item>
      <title>Safety Performance Analysis of TSMO: A Practical Approach for Assessing Safety Service Patrol Effects on Secondary Crashes</title>
      <link>https://trid.trb.org/View/1851825</link>
      <description><![CDATA[The Federal Highway Administration (FHWA) Office of Safety, in cooperation with the Highway Safety Manual (HSM) Implementation Pooled Fund Study, recently completed a safety analysis needs assessment for Transportation Systems Management and Operations (TSMO). The safety analysis needs assessment characterized the current state of practice, knowledge, and skills for quantifying the safety performance effects of TSMO. It also identified gaps in the existing body of knowledge and corresponding needs, which will provide the foundation for future research activities and advancements in practice. One group of needs focused on exploring sub-annual safety data collection and analysis methods to more effectively address the dynamic conditions under which TSMO strategies operate. This document presents one such sub-annual analysis method: a probabilistic model of crash occurrence to estimate the extent to which strategies that reduce primary incident clearance times affect the potential for secondary crashes. The analysis method is presented in the context of evaluating the secondary crash effects of safety service patrols (SSPs). The result of the analysis is a benefit/cost (B/C) ratio based on the expected change in secondary crash costs and the anticipated costs of SSP operation. The document also contains an example application of the 10-step approach based on a previously published analysis of an SSP program in Indiana. Because the SSP effects on secondary crashes are derived from reductions in traffic incident clearance times, the method can also be extended to other Traffic Incident Management (TIM) tactics or functions that are aimed at reducing incident clearance times.]]></description>
      <pubDate>Mon, 31 May 2021 20:13:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/1851825</guid>
    </item>
    <item>
      <title>Evaluating the impact of Road Rangers in preventing secondary crashes</title>
      <link>https://trid.trb.org/View/1849791</link>
      <description><![CDATA[Many transportation agencies utilize freeway service patrols (FSPs) to quickly identify and respond to incidents. The objectives of FSP are to minimize the incident duration and increase safety at the incident scene. The current research explored the safety benefits of Florida’s FSP program known as Road Rangers – harnessed from lowering the likelihood of secondary crashes (SCs) – compared to other responding agencies. The analysis was done on 6088 incidents that occurred on freeways in Jacksonville, Florida, from 2015 through 2017. Since SCs were not explicitly identified in the SunGuide® incident database, the study adopted a data-driven technique that used BlueToad® speed data to identify them. Once SCs were identified, a model was developed to identify factors influencing their occurrence. Factors such as an increase in equivalent hourly traffic volume, incident impact duration, and the percent of lanes closed significantly increased the likelihood of a SC. Besides, moderate/severe incidents, crash events, weekdays, peak hours, shoulder blockage, and incidents involving towing showed a high likelihood of resulting in a SC. Of practical importance, the model results revealed that a minute increase in incident impact duration increased the SC probability by 1.2 percent, with other factors held constant. Based on a 16-minutes decrease in incident impact duration, the Road Rangers program could lessen the probability of SCs by 21 percent, compared to other agencies. These findings could be beneficial to incident managers, responders, and researchers in evaluating the program’s performance.]]></description>
      <pubDate>Thu, 27 May 2021 12:37:03 GMT</pubDate>
      <guid>https://trid.trb.org/View/1849791</guid>
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