About the research
The current highway design guidelines for railroad signal and stop arm pole protection indicate that designers should place steel beam guardrail between the edge of the traveled way and the railroad pole in order to protect the fixed object hazard. Unfortunately, many of the poles are located in such a manner that they are within the deflection area of the steel beam guardrail, and thus the guardrail may not be able to protect an errant vehicle as desired, if at all. In fact, installing a steel beam guardrail may increase the likelihood of an incident as it replaces a point hazard with a longitudinal hazard and, if struck, may guide the vehicle directly into the pole.
In reviewing other state department of transportation (DOT) guidelines, some indicate that the poles should not receive protection if within 6 feet of the traveled way, likely due to the deflection area of a steel beam guardrail. Others indicate that a guardrail should not be placed unless protecting some other hazard (typically a steep slope).
An option other than using a steel beam guardrail would be to protect the railroad pole using a crash cushion. While crash cushions can be offset further from the traveled way, and thus reduce incidental hits, they are significantly more costly and may not provide a positive return on investment.
The goals of this study are as follows:
- Determine the crash rate into railroad poles without steel beam protection and compare to those with steel beam protection to determine if protecting against this hazard is actually reducing injuries
- Determine the benefit/cost ratio for protecting with steel beam guardrail or crash cushions given the crash rate per vehicle in relation to annual average daily traffic (AADT)
- Determine which railroad pole designs are breakaway, if any, such that they are designed to safely break away during a crash and thus would not warrant protection
- Survey state DOTs to determine best practices if a positive benefit/cost ratio is unattainable for a given AADT and the railroad pole is not breakaway