Pei-Sung Lin

Naturalistic Driving Study: Field Data Collection

This report describes the six Strategic Highway Research Program 2 (SHRP 2) naturalistic driving study (NDS) data collection centers and documents their data collection activities and strategies. The study centers were located in Bloomington, Indiana; State College, Pennsylvania; Buffalo, New York; Tampa, Florida; Durham, North Carolina; and Seattle, Washington. They collected data from more than 3,000 volunteer participants and their vehicles over a 3-year period. Information is provided on the recruitment and assessment of test participants, installation of NDS data acquisition systems into participant vehicles, management of the enrolled participants and their vehicles, retrieval of data from the vehicle fleet, and lessons learned. The report will be of interest to analysts wanting background on where and how the NDS data were collected and to researchers planning future large-scale NDS projects.

Aggressive Driving and Safety Campaigns: Lessons Learned from Better Driver Campaign in Florida

Aggressive driving is a growing concern in the United States. Often such driving results in crashes that harm both drivers and others. In NCHRP Report 500, “aggressive driving” is defined as “operating a motor vehicle in a selfish, pushy, or impatient manner, often unsafely, that directly affects other drivers.” In other words, aggressive driving includes many unsafe driving behaviors by ordinary drivers. Most previous safety campaigns have used enforcement interventions as the primary means of reducing aggressive driving. Enforcement clearly plays a crucial role in reducing aggressive driving. Limited efforts have been made, however, to enhance awareness of aggressive driving by providing proper education to the public. The Better Driver Campaign plan was developed and executed to address aggressive driving in Florida. The campaign was geared toward promoting awareness of aggressive driving. The education-oriented safety campaign was effective in addressing aggressive driving and was appreciated by the public.

An Overview of Yield-to-Bus Programs in Florida

This paper presents an overview of Yield-to-Bus (YTB) programs in Florida, including a review of bus operator surveys, operational and safety effects of YTB signage, and Florida YTB statutes. The statewide bus operators’ survey highlighted different aspects of YTB programs in Florida. First, it was apparent that bus operators often have difficulty moving back into the flow of traffic from any off-line position, including bus pullout bays, right-turn lanes, and wide paved shoulders. Even with the law implemented, motorists typically do not yield to the bus. The study found that the decal currently implemented on the back of the bus has no significant safety or operational effects, and there are no roadside signs or pavement markings for YTB laws.

Rearview Video System as Countermeasure for Trucks’ Backing Crashes: Evaluating the System’s Effectiveness by Controlled Test

In general, the operation of large trucks involves many different types of maneuvers. The backing maneuver, in particular, requires a higher level of driver attention because of the limited rear view. A growing number of trucks in the United States are equipped with a rearview video system (RVS) that can help the driver see much of the area behind the vehicle. An RVS consists of one or more cameras and one monitor. It is expected that an RVS can help drivers reduce potential backing crashes. To evaluate the effectiveness of the system, this study performed a controlled driver test with 45 truck drivers. The test used three backing maneuvers and a pedestrian dummy for observation of potential crashes. The results showed that the use of an RVS increased the stop rate of the drivers during the straight-line backing maneuver by 46.7%, which could be interpreted as an increase in the odds of avoiding potential backing crashes during the backing maneuver. The stop rate increased 4.4% and 17.8% for the offset right backing and alley dock backing maneuvers, respectively. Driver age, commercial driving experience, and experience with an RVS showed no statistical association with the increased stop rate, which means an RVS can be adopted by drivers quickly. In general, drivers showed positive attitudes toward using an RVS, and more than 90% of respondents agreed that an RVS could reduce the rear blind spot for large trucks.

Safety Effects of Horizontal Curve Design on Motorcycle Crash Frequency on Rural, Two-Lane, Undivided Highways in Florida

The association between horizontal curve design (e.g., radius and type) on rural, two-lane, undivided highways and motorcycle crash frequency is not well documented in existing reports and publications. This study aimed to investigate the effects of design parameters and associated factors on the occurrence of motorcycle crashes with consideration of the issue of unobserved heterogeneity. A random-parameters negative binomial regression model was developed on the basis of data on 431 motorcycle crashes, which were collected on 2,179 horizontal curves along two-lane, undivided highways in Florida for 11 years (2005 to 2015). Four normally distributed random parameters (i.e., logarithm of curve radius, reverse curves, pavement condition, and rough pavement indicator) were identified to represent their heterogeneity caused by unobserved factors over time, space, individuals, or some combination thereof. The major conclusions are the following: (a) an increase in curve radius, on average, significantly and near-logarithmically reduced motorcycle crash frequency on rural, two-lane, undivided highways (this effect was more significant when the curve radius was less than 2,000 ft); (b) 74.8% of reverse curves tended to reduce motorcycle crash frequency on rural, two-lane, undivided highways (for the remaining 25.2%, the effect had an opposite effect; on average, the likelihood of motorcycle crashes on reverse curves decreased by 39%); (c) the crash modification function (CMF) for curve radius on rural, two-lane, undivided highways was established, given the radius of 5,000 ft as the baseline, as a power formula, CMF = (radius/5,000)-0.208.

Modeling Safety Effects of Horizontal Curve Design on Injury Severity of Single-Motorcycle Crashes with Mixed-Effects Logistic Model

Horizontal curves have been of great interest to transportation researchers because of expected safety hazards for motorcyclists. The impacts of horizontal curve design on motorcycle crash injuries are not well documented in previous studies. The current study aimed to investigate and to quantify the effects of horizontal curve design and associated factors on the injury severity of single-motorcycle crashes with consideration of the issue of unobserved heterogeneity. A mixed-effects logistic model was developed on the basis of 2,168 single-motorcycle crashes, which were collected on 8,597 horizontal curves in Florida for a period of 11 years (2005 to 2015). Four normally distributed random parameters (moderate curves, reverse curves, older riders, and male riders) were identified. The modeling results showed that sharp curves (radius <1,500 ft) compared with flat curves (radius ≥4,000 ft) tended to increase significantly the probability of severe injury (fatal or incapacitating injury) by 7.7%. In total, 63.8% of single-motorcycle crashes occurring on reverse curves are more likely to result in severe injury, and the remaining 26.2% are less likely to result in severe injury. Motorcyclist safety compensation behaviors (psychologically feeling safe, and then riding aggressively, or vice versa) may result in counterintuitive effects (e.g., vegetation and paved medians, full-access-controlled roads, and pavement conditions) or random parameters (e.g., moderate curve and reverse curve). Other significant factors include lighting conditions (darkness and darkness with lights), weekends, speed or speeding, collision type, alcohol or drug impairment, rider age, and helmet use.

Landscaping of highway medians and roadway safety at unsignalized intersections

Well-planted and maintained landscaping can help reduce driving stress, provide better visual quality, and decrease over speeding, thus improving roadway safety. Florida Department of Transportation (FDOT) Standard Index (SI-546) is one of the more demanding standards in the U.S. for landscaping design criteria at highway medians near intersections. The purposes of this study were to (1) empirically evaluate the safety results of SI-546 at unsignalized intersections and (2) quantify the impacts of geometrics, traffic, and landscaping design features on total crashes and injury plus fatal crashes. The studied unsignalized intersections were divided into (1) those without median trees near intersections, (2) those with median trees near intersections that were compliant with SI-546, and (3) those with median trees near intersections that were non-compliant with SI-546. A total of 72 intersections were selected, for which five-year crash data from 2006-2010 were collected. The sites that were compliant with SI-546 showed the best safety performance in terms of the lowest crash counts and crash rates. Four crash predictive models-two for total crashes and two for injury crashes-were developed. The results indicated that improperly planted and maintained median trees near highway intersections can increase the total number of crashes and injury plus fatal crashes at a 90% confidence level; no significant difference could be found in crash rates between sites that were compliant with SI-546 and sites without trees. All other conditions remaining the same, an intersection with trees that was not compliant with SI-546 had 63% more crashes and almost doubled injury plus fatal crashes than those at intersections without trees. The study indicates that appropriate landscaping in highway medians near intersections can be an engineering technology that not only improves roadway environmental quality but also maintains intersection safety.

A Pilot Study on Interactions between Drivers and Pedestrian Features at Signalized Intersections-Using the SHRP2 Naturalistic Driving Study Data

This paper aims to assess driver behaviors at signalized intersections with four identified pedestrian features (“Stop Here on Red,” “No Turn on Red,” “Turning Vehicles Yield to Pedestrians,” and “Right on Red Arrow after Stop”) via a pilot study by using an innovative safety data: Strategic Highway Research Program 2 (SHRP2) Naturalistic Driving Study (NDS) data. The major findings from the pilot study include: (1) “No Turn on Red” has the highest rate of compliance (70%), followed by “Right on Red Arrow after Stop” (67%), “Turning Vehicles Yield to Pedestrians” (67%), and “Stop Here on Red” (55%); (2) compared to control group (without pedestrian features), three features (“Stop Here on Red,” “No Turn on Red,” and “Right on Red Arrow after Stop”) increased the likelihood of compliant behaviors; and (3) mid-aged drivers (25-59) showed the highest percentage of compliance at feature sits (83%), followed by older drivers (60+, 69%) and young drivers (16-24, 61%).

Impact of Connected Vehicles and Autonomous Vehicles on Future Transportation

Emerging vehicle technologies foreshadow a world in which sensors and software will replace humans in the driver’s seat. Connected and autonomous vehicle technologies are no longer a question of “if” but rather of “how” implementation will impact future transportation. This paper explores the safety and operational impacts of connected and autonomous vehicles on future transportation. Safety impacts include enhanced awareness of surroundings, driving assistance, crash avoidance, and reduced human error. Operational impacts include reduced traffic congestion, improved mobility, optimized freight flow and traffic control, etc. The paper also describes the potential challenges and concerns related to system imperfection, cyber security, insurance, mixed traffic flow, and consumer perception. Furthermore, the paper discusses how these advances of technologies will impact the infrastructure of transportation systems and the transportation engineers and professionals that operate and manage them. It offers great insights into the impact of connected and autonomous vehicles on future transportation.

Evaluation on the Perceived Effectiveness of Red RRFB Configurations to Reduce Wrong-Way Driving

Despite providing the necessary required signage and pavement markings as per the Manual on Uniform Traffic Control Devices (MUTCD), wrong-way entries onto freeway and limited access facilities continue to occur and lead to wrong-way crashes, which can be severe and even fatal. Yellow rectangular rapid flashing beacons (RRFBs) have been proven to be effective to alert drivers to yield to pedestrians crossing streets; however, the effectiveness of red RRFBs with specific configurations installed at freeway off-ramps on reducing wrong-way driving onto freeway mainlines were unknown. This research investigated various combinations of RRFBs and wrong-way signs and their location placement to determine the RRFB combination most preferred by the motoring public for implementation and to assess their perceived effectiveness via a detailed public opinion survey. Comprehensive analyses were conducted based on 296 participants’ answers to a series of survey questions after their reviews of field videos recorded from a driver’s angle. The survey results showed that a vast majority (69.5%) of survey participants selected the combination of placing “WRONG WAY” signs on both the left and right sides of an interstate off-ramp with red RRFBs activated at the top and bottom as the method that most gets their attention and informs them of wrong-way driving. Additionally, approximately 58% of participants selected the non-dimmed flashing red RRFBs over the dimmed option. This study offers important findings essential for the future determination of using red RRFBs as an optional supplement to the existing standards in MUTCD to reduce wrong-way driving.