+11 votes
by (100 points)
A westbound section of freeway currently has three 12-ft wide lanes, a 6-ft right shoulder, and no ramps within 3 miles upstream and downstream of the segment midpoint. It is on rolling terrain with 10% heavy vehicles and is operating at capacity with a peak-hour factor of 0.9. If the road is expanded to four 11-foot lanes with a 2-foot right shoulder, and traffic after the expansion is projected to increase by 10% with the same heavy vehicle percentage and peak-hour factor, what is the new LOS and estimated density?

1 Answer

+8 votes
by (100 points)
•Estimated density = 39.685Pc/mi/en•Level of service, LOS frequency = LOSCExplanation:We are given:•Freeway current lane width,B = 12ft• freeway current shoulder width,b = 6ft• percentage of heavy vehicle, Ptb = 10℅• peak hour factor, PHF = 0.9Let's consider,•Number of lanes N = 4• flow of traffic V = 7500vph• percentage of Rv = 0, therefore the freeflow speed in freeway FFS = 70mph• cars equivalent for recreational purpose Er= 2•cars to be used for trucks and busses Etb= 2.5Let's first calculate for the heavy adjustment factor.We have:Substituting figures in the equation we have:= 0.75Let's now calculate equivalent flow rate of the car using:= 2777.7 pc/h/enCalculating for traffic density, we have:D = 39.685 Pc/mi/enUsing the table for LOS criteria of basic frequency segment, the level of service LOS of frequency is LOSC
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