3.0 Signing, Markings and Channelization

3.5.4 Recommended Guidelines

Lane-use Signal Design Issues

• Location of the lane-use signal above the respective toll lanes must be selected to be clearly visible to approaching traffic well in advance of the toll lane and complement the lane status sign providing information on payment types supported in the lane. Vertical clearance and uniformity of signal location for each plaza must be maintained.
• Consistency with existing standard practices for roadway, bridge and tunnel designs, particularly for symbol type and display colors.
• Selection of conventional signal heads in lieu of arrow and “X” symbols needs to be considered from a user familiarity prospective that may have already been established from lane-use signal deployments on other facilities (both tolled and freeway) within a metropolitan statistical area or other defined region.
• From a safety perspective, color blind users will be considerably more likely to correctly interpret the arrow and "X" display than the traffic signal."
• Expended man-hours and lane closures to maintain each of the two signal types must be considered when selecting between traffic signal heads and customized displays.
• Spares and parts inventory must be assessed to avoid full unit replacement before the device reaches its useful life.

Lane-use Signal Guideline Development

• Location and mounting of lane-use signals should centered above each conventional plaza toll lane and attached to the canopy fascia below the lane status sign or supported from the underside of canopy, respectively. Alternatively, lane use signals can be mounted to a gantry or bridge structure located immediately in front of the canopy. A minimum vertical clearance of seventeen feet (17’) should be maintained based on national interstate bridge guidelines (AASHTO A Policy on Geometric Design of Highways and Streets). To the maximum extent possible, the mounting needs to accommodate easy access to the power and communication interconnections and provide clearance for accessing internal components.
• The lane-use signal should be designed as a larger version of the lane use signals specified by the MUTCD that are mounted overhead to gantries and bridge structures and centered above roadway, bridge and tunnel travel lanes. Provisions for consistency with these installations supports the recommended placement of the lane-use signal below the canopy sign. A red “X” should be displayed to indicate a closed state and a downward pointing green arrow should be displayed to indicate an open state. Lane –use signals should be visible from at least 600’ to allow users to make a timely decision on which lane to use for their transaction.
• If lane-use signals are currently in use within the metropolitan statistical area or other defined region encompassing the toll facility, either adoption of this lane-use signal or coordination with the agency deploying the existing signals to consider adopting a new signal should be pursued. Uniformity on a regional basis will assure user familiarity, which is expected to result in improved traffic flow.
• Maintenance considerations of the two types of lane-use signals (i.e., horizontally aligned signal heads or combined arrow and “X” display panels) result in the recommended use of LED technology for both designs. Use of incandescent light for the signal heads would require more frequent maintenance requiring capacity reducing lane closures, and thereby longer vehicle queues.
• Spares and parts must be procured to assure continuous operation of the lane-use signals that displays critical information to the user in making a timely determination of lanes available for their desired transaction type. This is expected to result in improved traffic flow.

Table of Contents | List of Tables | List of Figures | Previous Section | Next Section | HOME