  Although wireless technology is available for safety-critical applications,
few applications have been used to improve train crossing safety. To prevent
potential collisions between trains and vehicles, we present a Dedicated
Short-Range Communication (DSRC)-enabled train safety communication system
targeting to implement at unmanned crossings. Since our application's purpose
is preventing collisions between trains and vehicles, we present a method to
calculate the minimum required warning time for head-to-head collision at the
train crossing. Furthermore, we define the best- and worst-case scenarios and
provide practical measurements at six operating crossings in the U.S. with
numerous system configurations such as modulation scheme, transmission power,
antenna type, train speed, and vehicle braking distances. From our
measurements, we find that the warning application coverage range is
independent of the train speed, that the omnidirectional antenna with high
transmission power is the best configuration for our system, and that the
latency values are mostly less than 5 ms. We use the radio communication
coverage to evaluate the time to avoid collision and introduce the safeness
level metric. From the measured data, we observe that the DSRC-enabled train
safety communication system is feasible for up to 35 mph train speeds which is
providing more than 25-30 s time to avoid the collision for 25-65 mph vehicle
speeds. Higher train speeds are expected to be safe, but more measurements
beyond the 200 m mark with respect to a crossing considered here are needed for
a definite conclusion.
