Traffic Index, what does it really mean? 1

[harboe]

Hi, I have been asked to educate one of my my clients on what Traffic Index really means. I have not found any good resources that really explain it well.

Thanks in advance

 

[teeman]

An index is usually a representation of the change in some "data unit" over time. The Dow Jones Index and the Consumer Price Index are two of the most commonly cited indexes.

I'm not sure of the context of your question. There can be many types of traffic indexes. One might illustrate traffic growth over the past 50 years. Another could show the change in traffic volume on a road segment over a day, a week, or some other time period.

 

[harboe]

I was asking about the Traffic Index (TI) used for desing of a pavement section. I found out today that it is really just a number that correlates to the expected Equialent Single Axle Loads (ESAL's) for a given road section. This TI value is then used in conjuction with a soil's R value for an appropriate paving section.

 

[fel3]

Harboe…

The Caltrans (CA Dept of Transportation) "Highway Design Manual" defines the TI in §602.4. You can download the entire HDM by chapter at

http://www.dot.ca.gov/hq/oppd/hdm/hdmtoc.htm.

At a minimum, get Chapter 600, since it also shows design methods for both AC and PCC structural sections using the TI and R-value.

fel3