Passive railroad-highway grade crossings

af Søren Underlien Jensen

Executive summary

Empirical knowledge about human factors related specifically to road users at passive railroad-highway grade crossings with fast trains is very limited today. There exists no precise information about:

          Road users judgment of speed and distance of trains,

          Road users acceptance and rejection of lags to trains (time-to-arrival), and

          Real clearance times for motorized vehicles, especially for large trucks and agricultural vehicles with trailers at passive railroad-highway grade crossing of different gradients and pavement type and quality.

There is no doubt that road users underestimate train speed, when it runs more than 30-40 mph. But the significance of this underestimation is unknown in relation to the accident rate at passive railroad-highway grade crossing, where trains run 60-75 mph. Road users percentual underestimation of trains time-to-arrival at grade crossings become larger the closer trains are at crossings. This is due to systematic illusions within the human vision.

It is unknown whether perceptual fix points like signs along the rail line, ditch lights on trains or train design may reduce the underestimation of train speed and its influence on accident rate. Ditch lights on trains reduce the rate of accidents at passive grade crossings, but whether this is due to better recognition of train presence or better judgment of speed and distance is also unknown.

Danish standards for passive railroad-highway grade crossings appear inexpedient in poor sight conditions due to weather like fog, heavy rain, etc. Current Danish standards for sight distances are shown in section 2.3. The sight distance standards are not obeyed at several passive railroad-highway grade crossings, even far from.

If passive railroad-highway grade crossings are to exist in many years ahead then it would be relevant to know the basic relevant human factors in order to set up more cost-efficient safety measures. It is also relevant with regulatory guidelines for train speed if sight distances are not obeyed and during poor sight conditions due to weather.

The literature shows that several technical safety measures exist, which actually improve safety at passive railroad-highway grade crossings. Even driveways and dirt roads with poor pavement conditions are possible to make safer at railroad grade crossings at low costs e.g. by creating a perpendicular crossing, reducing gradients, increasing sight distances, etc. Besides technical safety measures, both campaigning and education may improve safety at grade crossings.

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