hello,

I am trying to gather statistics on general road infrastructre parts. One key stats I am looking for is the ratio of the steel guardrail used in roads per road length (m of guardrail / road length). I am trying to do a study for my class to show the size of steel used for road guardrail and anticipate its grwoth for the next few years per road length.

I am sure there is a rule of thumb that I can use but tried mutliple journals and was not successful.

Please help!

Thanks in advance.

RS

A couple of thoughts...

1) I don't think you are going to be successful using a single ratio because different kinds of road require vastly different amounts of guardrail. Obviously straight relatively flat roads require little guardrail, curvy mountainous roads require a lot. The type of terrain where future roads will be built has a large bearing on the amount of guardrail that will be needed. You may need to divide highways in to classes based on type, apply a ratio to each type, then predict guardrail trends for each type

2) Historical guardrail usage per road length is probably a not a good predictor of future guardrail use - at least not in the USA anyway. This is because the Federal Highway Administration (FHWA) ties strings to Federal Aid funding projects, and their policies affect guardrail usage. Design standards for new road construction or existing road rehabilitation require more guardrail and a higher standard for guardrail than was historically the case, so guardrail estimates for the future on new or rehab construction should be higher than what is indicated by historical data. However, the FHWA is also pushing money toward "pavement preservation" projects rather than new construction or rehab projects. These projects are more limited in scope and by definition may not include highway improvements needed bring the road up to modern standards. More preservation project miles and fewer rehab project miles mean less new guardrails. Whether these two FHWA policies mean a net increase or decrease in guardrail usage I don't know, but I know they influence present and future highway construction in such a way as to limit the usefulness of historical data without further analysis of the impact of past, present and future FHWA policies.

Ummmmm...if I had paid more attention to your title, which says "m/km," I might have guessed you aren't in the USA, and if not, all that stuff about FHWA policies is meaningless. But regardless of the country and road authority, changing policies and design standards must be considered if you are going to use historical data as an indication of the future.

Thanks million Hoaokapohaku;

I do agree on the type of roads and the ratio relation. I am actually doing the whole study on flat land , 15 degrees is the highest elevation. I even tried to find data on total installed in the US in order to get a common ratio although I know the accuracy will suffer but with no luck.

If anyone can direct me to a stats site on such lengths as total in the US then I can get this common ratio and perform a greater discount at the end result.

Thanks again..

yes I am studying the roads in countries in Asia but using the US and EU as comparative benchmark.

I don't know exactly where to find the data, but it probably exists in FHWA internal records. I'd start by calling people in the FHWA safety program. You can find a directory at of people in the safety program at, http://safety.fhwa.dot.gov/about/contactinfo.cfm. From that directory, I'd try one of the following first:

Highway Safety Improvement Program (HSIP) Karen Scurry 609-637-4207 Karen.Scurry@dot.gov
NCHRP Report 350 and AASHTO Manual for Assessing Safety Hardware Nick Artimovich 202-366-1331 Nick.Artimovich@dot.gov