Recommended Guidelines Automatic Barrier Gate Design Issues

5.4.4 Recommended Guidelines Automatic Barrier Gate Design Issues

• While the automatic barrier gate has historically been effective in discouraging violations, particularly in manual lanes, gates installed in automatic lanes can be problematic during ACM malfunctions and when the user fails to pay the toll. Each of these conditions requires quick identification of the problem and raising the gate remotely or on-site by a lane walker to release the user waiting to exit the lane. Remote rising of the gate is usually done from the nearest attended tollbooth or the toll plaza administration building. This results in vehicle processing delays and often causes longer plaza lane queues that increase the incident of unsafe lane changing. This problem is compounded if vehicle identification information is manually collected prior to releasing the vehicle.

• Although the automatic barrier gate technology has improved over the years, such as the reduction of moving parts, equipment malfunction periodically occurs. This condition first requires identification of the problem by either an attendant in the lanes, an on-site maintenance technician or the plaza supervisor stationed in the operations room of the toll plaza administration building. After manually locking the gate arm in an open position and clearing the lane, the agency can either close the lane or continue to operate with an open gate until operation of the gate is restored. As a minimum, this process causes processing delays resulting in longer plaza lane queues that increase the incident of unsafe lane changing. If the maintenance staff response to this malfunction is slow, the impact on plaza throughput and safe operations can be significant.

• In automatic lanes, the failure of the gate arm to rise to release a waiting vehicle because of a malfunction of the ACM or gate or a failure to pay the toll, may result in a broken gate arm when an impatient user is unwilling to continue waiting for an extended time period and breaks-off the gate arm. Depending on the extent of damage to the gate and the availability of spare gate arms, the time required to restore the lane could be significant. Temporarily closing the lane in lieu of operating without the benefit of a gate during high traffic periods will likely result in increased lane changes and longer queues resulting from a reduction in plaza throughput.

• The automatic barrier gate cabinet must be installed either a safe distance from the toll lane travelway and/or behind the front face of a toll island or raised barrier to avoid damage from passing vehicles. The length of the gate arm when in a horizontal (i.e., closed) position must be visible to all vehicles allowed to use the lane where it is installed.

• Since the majority of vendor furnished standard gate arms lengths are eight (8) and ten (10) feet, the selected arm length and setback from the travelway may leave a gap

AUTOMATIC BARRIER GATE DESIGN

Automatic Barrier Gate Guideline Development:

• Toll plazas configured with dedicated and/or express lanes are very likely to include violation enforcement equipment, such as cameras and image processors that capture license plate images of violating vehicles. Consequently, VES equipment can easily be installed in automatic lanes, particularly if these lanes also include ETC equipment, to capture the plates of users who fail to pay the toll due. Although violations in the manual lanes of plazas that offer multiple collection mode lanes are usually minimal, VES equipment can also be deployed to capture the license plate of violators in these lanes. The remaining benefit derived from barrier gates, specifically, reducing speed in lanes attendants must cross to safely get to their assigned tollbooth, is dependent on whether these lanes actually have a vehicle speed problem.

• Based on the above issues related to the installation of automatic barrier gates as well as the annual costs to maintain and repair the gates, automatic barrier gates should only be considered for installation in plazas that include ETC equipment when the attendant must cross more than one lane to safely reach their tollbooth. In plazas that do not include an ETC capability, gates are recommended for use in automatic lanes when there is an adjacent manual lane in addition to the plaza supervisor’s workstation functionality, to remotely open the gate. For toll island installation, the gate cabinet should be setback 12 inches from the face of the toll island or raised barrier.

• Under all circumstances, a ten (10) foot gate arm should be used to minimize the end gap within the toll lane without materially slowing the gate arm speed and to increase visibility of the arm to approaching vehicles. To further increase visibility, the gate arm finish should be striped using two distinct, contrasting colors. A breakaway gate arm assembly should be specified to minimize repair time when a vehicle collides with a gate arm.

Automatic Lane Barrier Gate Guidelines

Guideline Automatic Lane Barrier Gate Guideline 1

Title Provisions for Automatic Lane Barrier Gates in Toll Plaza Deploying VES Equipment

Text VES equipment should be used in lieu of automatic barrier gates unless vehicle speeds through the automatic lane pose a safety hazard to attendants who must cross more than one lane.

Commentary To avoid the revenue loss from opening the gate for customers who fail to fully pay the displayed toll, plus the operational costs incurred to assure the gate arm raises and to maintain the gates, VES equipment should be deployed instead of automatic barrier gates. The automatic barrier gate installed at the departure end of the toll island to control the flow of traffic through a lane should not be confused with a pedestrian gate installed on the toll island to prevent staff or visitors from walking into a toll lane. This particular gate is rarely automated.

State of the Practice and Recommendations on Traffic Control Strategies at Toll Plazas

AUTOMATIC BARRIER GATE DESIGN

Guideline Automatic Lane Barrier Gate Guideline 2

Title Provisions for Automatic Lane Barrier Gates in Toll Plazas with no VES Equipment Deployment

Text Barrier gates should only be deployed in these lanes if both the supervisor’s workstation functionality and an adjacent manual/attended lane toll terminal functionality are capable of remotely raising the gate in the automatic lane.

Commentary None.

Guideline Automatic Lane Barrier Gate Guideline 3

Title Provisions for Manual/Attended Lane Barrier Gates in Toll Plaza Deploying VES Equipment

Text VES equipment should be used in lieu of barrier gates unless vehicle speeds through the manual/attended lane pose a safety hazard to attendants who must cross the lane.

Commentary None.

Guideline Automatic Lane Barrier Gate Guideline 4

Title Barrier Gate Horizontal Clearance

Text For toll island installation, the gate cabinet should be setback 12 inches from the face of the toll island or raised barrier.

Commentary None.

Guideline Automatic Lane Barrier Gate Guideline 5

Title Barrier Gate Arm

Text A ten (10) foot gate arm attached to a breakaway assembly should be specified. The gate arm finish should be striped using two distinct, contrasting colors.

Commentary The 10 foot gate arm minimizes the end gap within the toll lane and maintains

good visibility to approaching traffic while compromising gate arm speed, albeit a small reduction.