13.5.3 Case C-Intersections with yield control on the minor road

Intersections with yield control on the minor roads should have two separate pairs of approach sight triangles as seen in
Figure 13-9
. A four-leg intersection requires sight triangles for left, right, and crossing maneuvers, while a three-leg intersection only requires left and right sight triangles. Adjustment factors should be applied to intersection sight distance on approach grades based on
Table 13-1
. Where adjustment factors cannot be applied, consideration should be given to installing regulatory speed signing to reduce speed or installing stop signs on one or more approaches.
Intersections with yield control on minor roads should consider two cases:
  • Crossing maneuver from the minor road; and
  • Left and right-turn maneuvers.
Crossing maneuvers from the minor road should use or exceed a time gap (
t
g
)(s) shown in
Table 13-3
. Left and right turns should use a time gap (
t
g
)(s) shown in
Table 13-5
.
Yield-controlled approaches generally need greater sight distance than stop-controlled approaches, especially at four-leg yield-controlled intersections where the sight distance needs of the crossing maneuver should be considered. If sight distance sufficient for yield control is not available, use of a stop sign instead of a yield sign should be considered. In addition, at locations where the recommended sight distance cannot be provided, consideration should be given to installing regulatory speed signing or other traffic control devices at the intersection on the major road to reduce the speeds of approaching vehicles.
Table 13-5: Time Gap for Left or Right Turn at Yield-Controlled Intersections
Design Vehicle
Time Gap (t
g
)(s)
Passenger car
8.0
Single-unit truck
10.0
Combination truck
12.0
Notes:
Time gaps are for a vehicle to turn right or left onto a two-lane roadway with no median. The table values should be adjusted for multilane roadways:
For multilane roadways or medians—For left turns onto two-way roadways with more than two lanes, including turn lanes, add 0.5 s for passenger cars or 0.7 s for trucks for each additional lane, from the left, in excess of one, to be crossed by the turning vehicle. Median widths should be converted to equivalent lanes.
For right turns, no adjustment is needed.