A section of a multilane highway is to be reconstructed toimprove the level of service. The section being considered is on a5.0% upgrade that is 3/4 mile long. The highway currently has4-lanes (2 in each direction – all are 12-ft lanes) with a two-wayleft-turn lane in the middle and 4 foot shoulders on the rightside. It is to be reconstructed into a 6-lane facility (3-lanes ineach direction) undivided facility but, due to commercialdevelopment surrounding the highway, must remain in the current 72foot right of way. There are currently 35 access points per mileand the free flow speed is determined to be 50 mi/h. It is knownthat the road currently operates at capacity with 420 trucks/buses(no recreational vehicles) during the peak hour, a peak hour factorof 0.95 and all-commuter traffic.
The redesign is to reduce the number of access points per mileto 10 and to reduce the grade to 4.0% for 3/4 mile. It is estimatedthat the new design will increase traffic by 13%.
- Determine the lane width and shoulder width combination thatwill maximize capacity given that the 3 lanes (each direction) mustfit within 36ft?
- For the maximum-capacity lane/shoulder combination chosenabove, determine the new design's level of service anddensity.
