Mobility and Safety Impact of Driveway Assistance Devices Were Evaluated in Four Two-Lane Two-Way Rural Work Zones in Ohio.
Muskingum
Evaluation of Driveway Assistance Devices in Signalized Work Zones
Summary Information
Part-width construction methods are commonly used on suburban and rural two-lane roadways, which require one-way travel along a two-way corridor in each direction. This method, however, presents challenges at driveways and low volume intersecting roads. Temporary traffic signal devices are a proven technology used for one-way operations in each direction on two-way roads but can cause substantial delays for all drivers. Driver Assistance Devices (DADs) have the potential to improve operations and safety by allowing motorists at driveways, especially at intersecting roads with low volumes, to join an existing queue of vehicles in the mainline in the same one-way direction of travel instead of calling for an additional phase at the temporary traffic signal specifically for driveway movements. This study evaluated DADs in comparison to traditional temporary traffic signals at driveways in four work zones along State Route 60, in Muskingum County, Ohio, a two-lane two-way rural minor arterial. The work zone configurations included the closure of one of two of the travel lanes for approximately 1000-feet in length while construction was occurring on the other lane. During construction, access from driveways was maintained by either a temporary traffic signal at each driveway or DAD signal at each driveway. Traffic at each end of each work zone was controlled by one additional temporary traffic signal. The study included a field analysis based on data collected in June, July and October of 2022, and a microscopic traffic simulation analysis to quantify operational and safety of both work zone driveway devices, a benefit-to-cost analysis, and user surveys.
METHODOLOGY
Video data were collected to collect volume, queuing, compliance, safety, and speed of vehicles within the work zone, both along the mainline and at the driveways. For two of the work zones, the data were continuously collected from June 28, 2022, to July 7, 2022 and for the other two work zones the data were collected from October 12, 2022 to October 19, 2022 for 24 hours every day. An online survey was administered through a weblink provided to households along State Route 60, regardless of whether their driveway utilized the DADs or not, to understand drivers’ perceptions of the DADs. Surveys were also administered to individuals involved in the construction of the State Route 60 project. The purpose of this survey was to gain insights to workers’, Ohio DOT employees’, and consultants’ perceptions of the relationship between temporary traffic control devices, highway safety in work zones, and construction productivity when comparing the DAD devices with temporary traffic signal devices. To further investigate the operational and safety impacts of DADs, a microsimulation-based analysis was also performed. Utilizing vehicle trajectory outputs from the simulation model, conflict analyses were carried out using the Federal Highway Administration’s Surrogate Safety Assessment Model to assess the safety performance of the work zone segments.
FINDINGS
- Field analysis results indicated that the DADs reduced driveway waiting time by 46 percent and reduced mainline vehicle speeds and mainline queue lengths by 28 percent and 32 percent, respectively, compared to temporary traffic signals.
- Field analysis results also showed that the compliance rate for the DADs was higher than that for temporary traffic signals (22.7 percent for temporary traffic signals versus 80 percent for the DADs).
- The overall benefit-to-cost ratio only considering the device and maintenance cost was 7.6, whereas when the road user costs (excluding the conflict costs) were included, the ratio was 153.37. It should be noted that due to the small sample size of the field data evaluation, the microsimulation operational parameters were utilized in the benefit-to-cost analysis.
- Microsimulation analysis revealed that compared with traditional temporary traffic signals, the DAD devices have statistically shorter wait times (1.77 seconds compared to 23.61 seconds) and shorter queue lengths (0.14 feet compared to 0.52 feet) at the driveways for vehicles trying to merge into the mainline traffic flow.
- Based upon the household surveys, the majority of respondents (over 60 percent) understood the movements that were allowed under the DADs signal configuration.
- The results of the survey conducted with the people involved in the construction revealed that most of the survey respondents felt the DADs provided improved safety (84.62 percent of the respondents), and increased construction productivity (92.31 percent of the respondents).
