High-speed rail track systems, rights of way and station facilities located outside urban areas should contribute little in the way of traffic congestion to localized or extended streets or highway systems. Traffic delays at rural rail crossings would not be expected to create traffic congestion on any but heavily traveled highways. Wherever tracks cross roadways in locations where any level of commuter or urban traffic is concentrated, the potential for delays and congestion will occur. Under such conditions, crossing gates and all forms of safety equipment and procedures necessary for protection of vehicles, pedestrians and other crossing traffic must take priority.
Where high-speed rail tracks enter urban areas, although train speed may be significantly reduced, the effects of regular or frequent blocking of crossing traffic may lead to delays and congestion of streets or highways in the vicinity of crossing gates and other safety equipment. Where such disruption of traffic can be anticipated, grade separations, realignment of streets or tracks, adjusting of train schedules and other accommodations or congestion-mitigating measures may be required, and should be considered in early planning stages.
Congestion relief attributed to high-speed rail services may prove difficult to identify or measure. Inter-city auto travel seldom produces traffic volume or concentrations that would produce congestion along hundreds of miles between cities, with the exception of the frequent delays, congestion and stoppages that occur on Interstate 15, between Las Vegas and Los Angeles, although the causes of the incidents are seldom attributable to traffic volume alone. Inter-city high speed rail services are characteristically designed as alternatives to air travel, or as significantly shorter travel alternatives to auto travel. In most cases, the routes of high-speed rail and inter-urban highways do not coincide or cross with any frequency.