UFC 4-022-01
25 May 2005
controllers. However, this curb height can place the checkers too high above the
seated drivers. Therefore, if curbs higher than 6 in (152mm) are used, provide "curb
cuts" or a step down to position security personnel at the proper working level.
If a gutter has a different color and texture than the road surface and has a longitudinal
joint, it should not be considered part of the travel lane width. One exception to this is
the total lane width at ID checkpoints, which should be either 10 feet (3.04 m) or 12 feet
(3.66 m), as previously identified.
6-6.5.2 Shoulders
Shoulders are discouraged near an ECF because motorists tend to go faster where
there are shoulders. Shoulders also make it harder to constrain and control the
movement of vehicles. If used, shoulders should be 6 ft (1.83 m) to 8 ft (2.44 m) wide,
and all fixed objects, such as signs, trees, and posts, should be at least 6 ft (1.83 m)
from the edge of the shoulder or 12 ft (3.65 m), from the edge of the travel lane. Where
a road edge changes from a shoulder to a curb, the transition area should be gradual,
with a minimum taper ratio of 10 to 1, to give the driver time to react.
6-6.6
Transitions and Tapers
When lanes are redirected, dropped, or added, provide proper transitions to enhance
traffic flow and ensure safety (Traffic Engineering and Highway Safety Bulletin: Traffic
Engineering for Better Gates.) The transition allows drivers the opportunity to recognize
the change and react appropriately. A common flaw is that road transitions are often
too short. At a minimum, provide transitions to redirect lanes at channelization islands.
Lane tapers allow drivers to respond to a change in road alignment. Tapers should be
used when lanes are separated on the approach to a gate island or lanes on a road are
added or dropped before or after a gatehouse. Traffic and Safety Engineering for Better
Entry Control Facilities provides transition and taper length criteria.
6-6.7
Roadside Safety
Determine barrier end treatments and the need for crash cushions in accordance with
RSDG-3, Roadside Design Guide, latest edition. Transportation Research Board
National Cooperative Highway Research Program (TRB NCHRP), Report 350
"Recommended Procedures for the Safety Performance Evaluation of Highway
Features" provides guidelines on testing and evaluating safety features, as well as
providing a basis for formulating performance specifications for safety features.
6-6.8
Lateral Clearances
Lateral obstructions present a safety hazard and tend to negatively impact traffic flow.
The negative effects are eliminated or reduced if the object is less than 6 in (152 mm)
high or located at least 6 ft (1.8 m) from the edge of the roadway (Traffic and Highway
Engineering.) Ideally the lateral clearance would be greater. Therefore, the location of
lateral obstructions in the approach and response zones, including the passive vehicle
barriers, should be a minimum of 6 ft (1.8 m) from the edge of roadway.
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