Traffic Engineering question on volumes

[RDK]

I am reviewing a report that has some average daily traffic volumes.

I am interested in an estimation on peak hourly volumes.

Can anyone provide a rule of thumb that give the ratio or range in ratios between these two traffic counts. The road will be in a third world country and be a toll road to US interstate standards.

My concern is that the projected increases will at some time exceed the peak capacity of the proposed roadway.

The current ADT is around 15,000 vehicles per day. This would be 7,500 each way and the proposed road would have two lanes each direction. The peak hourly capacity is about 1,600 per lane (if I remember my traffic courses from 30 years ago) and they are predicting annal increases of around 3% per year.

My problem is to determine when they will need to expand the highway to accomidate the traffic increase.

Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com

 

[ACtrafficengr]

In this part of the US, peak hour volume is usually 11% of ADT in urban areas, 15% in rural areas. This can vary widely, so I'm not sure if I'd rely on a rule of thumb. I'd ask the report writer for hourly volumes.

1600 vpl is low for NY State, but this also varies.

------------------------------------------
"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail."

Wm. Phelps Eno, ca. 1928

 

[Matterafact]

RDK - A simple method in common use today is compound growth equation.
F = Future Traffic
P = Current Trffic
i = rate of increase (divided by 100)
n = number of years out into the future.

F = P(1+i)^n If this formula looks familar it should. It is compound instrest. Traffic Impact studies use it too.

At the end of the day it's always best to give a range as I'm sure you know. =)

Engineer
Bartlesville, OK