Using Naturalistic Driving Study Data to Evaluate the Effects of Intersection Balance on Driver Behavior at Partial Cloverleaf Interchange Terminals
This study utilizes the Naturalistic Driving Study (NDS) data to evaluate the effects of intersection balance on driver behavior at parclo interchange terminals. It demonstrates statistical characteristics and overall trends of driver speed, acceleration/deceleration rates, and risk perception with the changing of intersection balances. Conclusions provide guidance on optimal intersection balance design that may help drivers make smoother and safer transitions from crossroads to entrance ramps at parclo interchange terminals.
Forward View - color
Right-Rear View
Location 3 with marked approaches of interest
Forward View - color
Relationship between Geometric Elements and Wrong-Way Crashes at Partial Cloverleaf Interchange Terminals
For partial cloverleaf (parclo) interchange terminals with close-spaced two-way ramps, good terminal geometric elements satisfy drivers’ accessibility and safety needs. This paper quantifies the relationship between geometric elements and wrong-way crashes at parclo interchange terminals. Recommendations were made on geometric design and countermeasures of interchange terminals for wrong-way movement reduction.
Geometric elements at partial cloverleaf interchange terminals
Current best practice of Intersection Balance
Example of unbalanced intersections
Geometric elements at partial cloverleaf interchange terminals
Drivers’ wrong-way movements from crossroads to divided highways
Diagram of the measured parameters
Example of profile drawing for median-crossroad intersections
Drivers’ wrong-way movements from crossroads to divided highways
In-Depth Investigation of Wrong-Way Crashes on Divided Highways in Alabama Using Haddon Matrix and Field Observations
Few studies exist on wrong-way driving (WWD) on divided highways. Previous findings on contributing factors and countermeasures are mostly on freeways. This study fills the gap by conducting an in-depth investigation of WWD crashes exclusively on divided highways in Alabama. Extensive efforts were made on WWD crash data analysis using Haddon Matrix and field observations. General issues, contributing factors, and countermeasures were identified through in-depth analyses of individual crashes and field review of crash locations and WWD entry points. Conclusions and recommendations were made to reduce the possibility and severity of WWD on divided highways.
Comparison of the Green Arrow and the Circular Green for Turn Prohibition to Reduce Wrong-Way Movements at Interchange Terminals
Most wrong-way crashes with known entry points on freeways originate from interchange terminals. Some traffic agencies have replaced Circular Greens (CGs) with Green Arrows (GAs) to provide better lane-use indications to deter wrong-way turns. However, the effectiveness of the strategy has not been well studied. The study fills the gap and develops guidelines for the application circumstances of GAs and CGs to mitigate WWD at interchange terminals and sets a starting point for further investigations and potential revisions in future editions of the MUTCD.
Green Arrow + turn-prohibition sign (LED), Chicago IL
GA + regular turn-prohibition sign, Birmingham AL
CG + regular turn-prohibition sign, Montgomery AL
Green Arrow + turn-prohibition sign (LED), Chicago IL
Intersection Balance at signalized ramp terminals of partial cloverleaf interchanges (WSDOT 2013)
Median barrier blocking driver view of the entrance ramp (Google Map)
Illustration of driver view
Intersection Balance at signalized ramp terminals of partial cloverleaf interchanges (WSDOT 2013)
Improve Sight Distance at Signalized Ramp Terminals of Partial Cloverleaf Interchanges to Deter Wrong-Way Entries
This research provides a comprehensive evaluation of the impact of stop line positioning based on wrong-way crash data analysis. Effects of different lengths of the median barriers used to separate two-way ramps on left-turn drivers’ sight distance were also investigated by analyzing drivers’ perspectives of roadway information with a three-dimensional (3D) simulation and analytical methodology. Conclusively, the current best practice was proven effective in deterring wrong-way driving, and general guidelines for appropriate median barrier lengths on two-way ramps were developed.