Emission model sensitivity analysis: The value of smart phone weight-mile tax truck data

This research serves to evaluate the potential use of a system developed by the Oregon Department of Transportation (ODOT) for emission estimates. The data collection system developed by ODOT – Truck Road Use Electronics (TRUE) – includes a smart phone application with a Global Positioning System (GPS) device and microprocessor. Previous research with the TRUE data served to demonstrate its use for important ancillary applications such as highly accurate trip generation rates and m obility performance measures. In addition, it was shown that the TRUE data has strong potential use for safety, accessibility and connectivity, system condition and environmental stewardship performance measures. This new research builds on that past work and evaluates the potential use of the TRUE data for emissions estimates that take into account truck type details, truck weight and detailed speed profiles. A sensitivity analysis using the U.S. Environmental Protection Agency's (EPA) Motor Vehicle Emissi on Simulator 2010b (MOVES2010b) is performed in order to understand the level of error that might be encountered when such detailed data are not available. The impact of grade on emissions estimates is also considered. Results indicate that TRUE data in in tegration with Oregon Department of Transportation (ODOT) weight - mile tax (WMT) data will greatly improve the accuracy of emissions estimations at the project and regional level

Multimodal Data at Signalized Intersections: Strategies for Archiving Existing and New Data Streams to Support Operations and Planning & Fusion and Integration of Arterial Performance Data

There is a growing interest in arterial system management due to the increasing amount of travel on arterials and a growing emphasis on multimodal transportation. The benefits of archiving arterial-related data are numerous. This research report describes our efforts to assemble and develop a multimodal archive for the Portland-Vancouver region. There is coverage of data sources from all modes in the metropolitan region; however, the preliminary nature of the archiving process means that some of the data are incomplete and samples. The arterial data sources available in the Portland-Vancouver region and that are covered in this report include data for various local agencies (City of Portland, Clark County, WA, TriMet and C-TRAN) covering vehicle, transit, pedestrian, and bicycle modes. We provide detailed descriptions of each data source and a spatial and temporal classification. The report describes the conceptual framework for an archive and the data collection and archival process, including the process for extracting the data from the agency systems and transferring these data to our multimodal database. Data can be made more useful though the use of improved visualization techniques. Thus as part of the project, a number of novel, online visualizations were created and implemented. These graphs and displays are summarized in this report and example visualizations are shown. As with any automated sensor system, data quality and completeness is an important issue and the challenge of automating data quality is large. Preliminary efforts to validate and monitor data quality and automate data quality processing are explored. Finally, the report presents efforts to combine transit and travel time data and signal timing and vehicle count data to generate some sample congestion measures

Pedestrian Behavior Study to Advance Pedestrian Safety in Smart Transportation Systems Using Innovative LiDAR Sensors

Pedestrian safety is critical to improving walkability in cities. Although walking trips have increased in the last decade, pedestrian safety remains a top concern. In 2020, 6,516 pedestrians were killed in traffic crashes, representing the most deaths since 1990 (NHTSA, 2020). Approximately 15% of these occurred at signalized intersections where a variety of modes converge, leading to the increased propensity of conflicts. Current signal timing and detection technologies are heavily biased towards vehicular traffic, often leading to higher delays and insufficient walk times for pedestrians, which could result in risky behaviors such as noncompliance. Current detection systems for pedestrians at signalized intersections consist primarily of push buttons. Limitations include the inability to provide feedback to the pedestrian that they have been detected, especially with older devices, and not being able to dynamically extend the walk times if the pedestrians fail to clear the crosswalk. Smart transportation systems play a vital role in enhancing mobility and safety and provide innovative techniques to connect pedestrians, vehicles, and infrastructure. Most research on smart and connected technologies is focused on vehicles; however, there is a critical need to harness the power of these technologies to study pedestrian behavior, as pedestrians are the most vulnerable users of the transportation system. While a few studies have used location technologies to detect pedestrians, this coverage is usually small and favors people with smartphones. However, the transportation system must consider a full spectrum of pedestrians and accommodate everyone. In this research, the investigators first review the previous studies on pedestrian behavior data and sensing technologies. Then the research team developed a pedestrian behavioral data collecting system based on the emerging LiDAR sensors. The system was deployed at two signalized intersections. Two studies were conducted: (a) pedestrian behaviors study at signalized intersections, analyzing the pedestrian waiting time before crossing, generalized perception-reaction time to WALK sign and crossing speed; and (b) a novel dynamic flashing yellow arrow (D-FYA) solution to separate permissive left-turn vehicles from concurrent crossing pedestrians. The results reveal that the pedestrian behaviors may have evolved compared with the recommended behaviors in the pedestrian facility design guideline (e.g., AASHTO’s “Green Book”). The D-FYA solution was also evaluated on the cabinet-in-theloop simulation platform and the improvements were promising. The findings in this study will advance the body of knowledge on equitable traffic safety, especially for pedestrian safety in the future

Safest Placement for Crosswalks at Intersections

This research studied the relationship between crosswalk setback and intersection safety. The study included field-based and driving simulator experiments. Video data was collected at 10 crosswalks in Oregon to examine the frequency pedestrian-vehicle conflicts (measured using PET), including how these conflicts vary between corner and setback crosswalks. A total of 507 pedestrians and 47 conflicts with post-encroachment times of less than 5 seconds were observed. The 50 participants driving simulator experiment was used to determine how setback distances, curb radii, and presence of pedestrians affect driver stopping decision and position, speed choice, visual attention, and level of stress. Observations of drivers\u2019 speed in a similar scenario were taken from field and simulator data to enhance the evidence provided by each experiment. Stop line speeds were found to be consistent between experiments and turning speeds were found to be slightly higher in the driving simulator experiment. The study results suggest that curb radius should be smaller to control driver speed. Additionally, setback distance of the crosswalk of 20ft is a suitable upper bound when reconstructing intersections

Quantifying the Performance of Low-Noise Rumble Strips

SPR 800Shoulder or centerline rumble strips (RS) generate noise and vibration to alert drivers when they are departing the lane of travel. Although inexpensive to install, easy to maintain, and very long-lasting, RS are not installed on many roadway segments primarily due to noise concerns of nearby property owners. This study evaluated the feasibility of using sinusoidal RS as a substitute for rounded milled RS on roadway segments in Oregon with lane-departure crash problems. Exterior and interior sound levels and interior vibrations generated by rounded and sinusoidal RS strikes were compared to baseline and no-strike sound levels for 3 vehicle classes (passenger car, van, and heavy vehicle) to establish sound generation and alerts of the 2 designs. A total of 114 vehicle strikes of RS were recorded. Rumble strip strikes by the passenger car and van generated less exterior noise with the sinusoidal than with the rounded design. Interior noise generated by striking the sinusoidal design generated a clearly noticeable alert, suggesting that the sinusoidal rumble strip is still an effective countermeasure. Based on thresholds of human perception for vibration, both rumble strip types generated sufficient vibration to alert the driver. Results for the heavy vehicle were complicated due to bridging of the harrower rounded rumble strip by the tires. The wider cut of the sinusoidal RS generated a clearly detectable increase in exterior roadside noise for the Heavy Vehicle. Likewise, the sinusoidal design created a noticeable interior alert for the HV but the rounded design did not

Exploring Thresholds for Timing Strategies on a Pedestrian Active Corridor

Traditional signal timing policies have typically prioritized vehicles over pedestrians at intersections, leading to undesirable consequences such as large delays and risky crossing behaviors. The objective of this paper is to explore signal timing control strategies to reduce pedestrian delay at signalized intersections. The impacts of change in signal controller mode of operation (coordinated vs. free) at intersections were studied using the micro-simulation software VISSIM. A base model was developed and calibrated for an existing pedestrian active corridor. A hypothetical network of three intersections was used to explore the effects of mode of operation and measures of delay for pedestrians and all users. From a pedestrian perspective, free operation was found to be more beneficial due to lower delays. However, from a system wide (all user) perspective, coordinated operation showed the greatest benefits with lowest system delay under heavy traffic conditions (v/c \u3e 0.7). In the off-peak conditions when traffic volumes are lower, free operation resulted in lowest system delay (v/c \u3c 0.7). During coordination, lower cycle lengths were beneficial for pedestrians, due to smaller delays. The results revealed that volume to capacity (v/c) ratios for the major street volumes coupled with pedestrian actuation frequency for the side street phases, could be used to determine the signal controller mode of operation that produces the lowest system delay. The results were used to create a guidance matrix for controller mode based on pedestrian and vehicle volumes. To demonstrate application, the matrix is applied to another corridor in a case study approach

Safety Effectiveness of Pedestrian Crossing Enhancements

Over the last decade, the Oregon DOT and other agencies have systematically implemented many pedestrian crossing enhancements (PCEs) across the state. This study explored the safety performance of these enhanced crossing in Oregon. Detailed data were collected on 191 crossings. Supplemental data items included crossing location information, route characteristics, surrounding land use and crossing enhancement descriptions. Pedestrian volume at the crossing locations was a highly desirable but unavailable data element. To characterize pedestrian activity, a method was developed to estimate ranges for pedestrian crosswalk activity levels based on the land use classification at the census block level and the presence of pedestrian traffic generators such as bus stops, schools, shopping centers and hospitals within a 0.25-mile radius. Each crosswalk was categorized into one of six levels of activity – very low, low, medium-low, medium, medium-high and high. Crash data for the 2007-2014 period were assembled for the safety analysis. After filtering, 62 pedestrian crashes and 746 rear-end crashes were retained for further analysis. The crash data were merged and analyzed. Crash patterns and risk ratios were explored. The most important trend observed was a shift (reduction) in the pedestrian crash severity after the installation of the crosswalk treatments. This shift was from fatal and injury A crash type to lower severity crashes of injury B and injury C. For pedestrian crashes, increases in the risk ratio were observed for increases in the number of lanes, the posted speed, and estimated pedestrian activity level. Similar trends were observed for rear-end crashes. Due to data limitations, subsequent safety analysis focused on installations of RRFB crossing enhancements. A CMF for RRFB installations was estimated. The CMFS for pedestrian crashes are 0.64 +/- 0.26 using a simple before-after analysis; for rear-end crashes: 0.93 +/- 0.22 using an empirical Bayes analysis approach

Driver Yielding and Pedestrian Performance at Midblock Crossings on Three-Lane Roadways with Rectangular Rapid Flashing Beacons

Rectangular rapid flashing beacons (RRFBs) have proven to be a useful tool for improving driver yielding and pedestrians’ safety at midblock crossings. This study analyzed driver yielding at 23 RRFB-enhanced midblock crossings on three-lane roadways with and without median refuge islands in Oregon. The locations were chosen to represent a range of posted speed limits and average daily traffic that aligns with existing guidance for median and beacon installations. Sites were classified either as (a) no median refuge, RRFBs placed outside the roadway, (b) median refuge, RRFBs placed outside the roadway, (c) median refuge, RRFBs placed on the island and outside the roadway. Yielding was determined following protocols established in prior research. Two hundred seventy-six hours of video footage were analyzed, resulting in 3,065 crossing events (1,338 staged; 1,727 naturalistic) undertaken by 3,683 pedestrians. High yielding rates were observed—the average near side yielding rate was 97%, with the lowest site having a rate of 89.9%. Yielding rates were generally higher on the far side. Owing to sample size and consistently high yielding rates, it was not possible to make conclusive observations about the relationship between driver yielding and the presence of median or additional beacons for the volume and speed combinations. The results generally indicated that yielding rates increased with the addition of median beacons. The findings also suggested median refuge islands with a beacon increased yielding. The increase in yielding was statistically significant at sites with average daily traffic of 12,000 to 15,000. Over the last decade, many jurisdictions in the United States have installed pedestrian crossing enhancements (PCEs) to improve pedestrian safety and experience. These enhancements include continental markings, median refuge islands, curb bulb-outs, pedestrian-activated flashing beacons, overhead signs, advanced stop bars, and most recently, rectangular rapid flashing beacons (RRFBs). FHWA first issued Interim Approval (IA-11) for the use of RRFBs in 2008 (1), then rescinded it in December 2017 because of patent issues. However, on March 20, 2018, FHWA issued Interim Approval for the optional use of pedestrian-actuated rectangular rapid-flashing beacons at uncontrolled marked crosswalks (IA-21) after the patent issues were resolved. In recent years, several studies have been carried out to evaluate the effectiveness, measured by driver yielding rates, of RRFBs at midblock crossings (2–12). These studies have used either staged pedestrian crossings, naturalistic observations, or both to evaluate driver yielding behavior. A wide range of driver yielding rates have been observed, ranging from 19% to nearly 98%, though there are differences in how yielding is defined. Other studies have also evaluated the safety effectiveness of RRFBs and found crash modification factors of 0.53 and 0.71, indicating a significant reduction in pedestrian–motor vehicle crashes postinstallation (13, 14). Other features of enhanced crossings such as raised medians have been found to significantly lower pedestrian crash rates along multilane roadways at both marked and unmarked crosswalk locations (15). Other research has also demonstrated safety benefits for pedestrians from raised medians and refuge islands as individual enhancements (16–18). However, no studies have been found to evaluate the combined effect of median refuge islands and RRFBs. Since RRFBs are primarily used at midblock crossings, the first decision an agency often faces is whether to mark the crossing or not. Subsequent decisions for the agencies include the type of crossing enhancement to install and whether RRFBs are suitable for that location. The guidance set forth by FHWA presents the range of conditions for which RRFBs should be considered a treatment option. The guidance has number of lanes (two, three, four, or more), posted speed limit (≤30 mph, 35 mph, ≥40 mph) and vehicle volume (15,000 ADT) (19). This research aimed to explore driver yielding on three-lane roadways, with and without median refuge islands. This research observed driver yielding behavior in Oregon at 23 midblock crossings on three-lane roadways equipped with RRFBs with and without median refuge islands and beacons. Twelve hours of video footage was collected and coded at each site. Both staged pedestrian crossings and observations of naturalistic crossings were analyzed for pedestrian performance measures and drivers’ yielding behavior. The remainder of the paper is organized in the following manner. A description of data collection and coding is next, followed by the results and analysis, and finally, our conclusions

Improved Safety and Efficiency of Protected/Permitted Right Turns in Oregon

This research aimed to develop an understanding of the safety and operational implications of using the flashing yellow arrow (FYA) in permitted and protected/permitted right turn (PPRT) operations to maximize safety and efficiency. This report includes a review of more than 50 scientific and technical articles on the selection of right turn phasing alternatives and a review of Oregon crash data at intersections with exclusive right-turning lanes from 2011-2013. The study had three phases: 1) a web-based survey, 2) a microsimulation model, and 3) and a driving simulator study. The survey measured Oregon driver’s comprehension of right-turn signal display. Analysis revealed a general misunderstanding of the required driver response for the steady red arrow signal indication, but comprehension of the FYA for right turns was high. The microsimulation model of several PPRT phasing alternatives indicated that the pedestrian volumes had the greatest effects on delays. The driving simulator experiment indicated that driver responses were relatively consistent with those observed in the web-based survey. The results suggest that Oregon transportation agencies might improve driver-yielding behavior and pedestrian safety at signalized intersections with high volumes of permissive right turns from exclusive right-turn lanes by using the FYA display in lieu of a steady circular green display

Systemic Opportunities to Improve Older Pedestrian Safety: Merging Crash Data Analysis and a Stakeholder Workshop

This paper presents a framework for improving older pedestrian safety in regard to serious (fatal and incapacitating) crashes, using Oregon as a case study. On review of state and federal practices pertaining to older pedestrian safety, 4 years of crash data identified 112 older (≥ 65 years) pedestrian serious injury crashes. These data were explored for factors that might be addressed systemically using two methods. First, raw frequencies in the crash data were assessed to determine trends and crash-related factors that are overrepresented. Second, a random forest analysis was conducted to determine important variables for predicting older pedestrian serious injury crashes. Using these crash-related factors, a workshop was held with 18 local stakeholders and experts. As part of the workshop, key crash trends, potential causations, and potential countermeasures by priority of implementation were determined based on perspectives from workshop participants. Three key systemic solutions were identified to improve older pedestrian safety, including improving pedestrian visibility and illumination, implementing treatments for left turns, and shortening pedestrian crossing distances across the state. The framework presented in the current study could be adopted by other agencies to systemically address a wide variety of safety concerns