7.2.3 Transitions to Four-Lane Divided Highways

Typical transitions from a two-lane to a four-lane divided highway are shown in
Figure 7-7
.
Transition geometrics design criteria is based on the highest design speed of the two roadways.
 The transition should be visible to the driver approaching from either direction and median openings should not be permitted within one-quarter mile of the transition area.
Transition areas should be located so that obstructions such as restrictive width bridges or underpasses or other fixed objects are not within the no-passing zone of the two-lane highway approach.
Typical Transistions from Two-Lane to Four-Lane Divided Highways ( click in image to see full-size image)
Figure 7-7: Typical Transistions from Two-Lane to Four-Lane Divided Highways