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41 4.2 Causes and Locations Lack of advance signing on crossroad approaches to of Mobility Constraints interchanges Road construction activities 4.2.1 Highways Lack of traffic signals timed for large truck movements in Many causes of freight mobility constraints on the highway areas of heavy truck volume system were noted by the respondents to the surveys and inter- Slow driver check-in/check-out at ports views. While many of the constraints affect only specific loca- Lack of 24/7 access to intermodal facilities tions, corridors, regions, or types of facilities, others are more Poorly marked alternate routes systemic to the interstate highway system and can impact inter- Inadequate traveler information on incidents and roadway national freight movements. In addition, the causes of mobil- status. ity constraints are frequently interrelated. Regulatory/Policy Constraints Physical Constraints Regulatory actions or public policies also play a major role Physical infrastructure deficiencies are the most prevalent in restricting truck freight movement. Public policies or regu- constraints cited by respondents. These deficiencies may be lations that negatively impact efficient freight movement vary system-wide or site specific. Examples of physical constraints in scope and range from local to international. Local route on the highway system include: restrictions, zoning laws, and parking restrictions may limit truck access to various areas. At the state level, it may be a lack Ramp meter locations that cause trucks to stop at a ramp of alternate routes for trucks or alternate routes with insuffi- terminal before attempting to merge into high-speed traffic cient signage. A lack of regulatory harmonization between Long, steep grades lacking passing lanes, particularly on different jurisdictions (e.g., cities, states, countries) can also mountainous roads constrain freight movement. Inadequate radii of loop ramps, at intersections or drive- The most often cited national policy-based constraints are ways into freight generators safety- and security-related restrictions and regulatory compli- Obsolete freeway ramps that were built in an era of shorter ance. These policies may restrict freight mobility on several trucks/trailer combinations with shorter turning radii levels, create delay, and increase motor carrier costs. Inter- Inadequate vertical or horizontal clearances (low bridge national shipments by land face delay at U.S. border crossings clearance--insufficient height for containers) as a result of security regulations, while local security regulations At-grade highway rail crossings in the vicinity of freight limit truck access to many office buildings and government generators facilities. Other types of policy-based constraints impose bur- Lack of adequate ingress/egress gates at ports, intermodal dens on the efficient movement of freight. These may include: terminals, or rail classification yards Increase in intermodal freight traffic near major ports such A lack of interoperability or reciprocity in the use of toll as in Southern California without a commensurate increase passes/transponders that are issued by various states; trucks in capacity to local infrastructure will need several passes to travel between states Lack of sufficient rest area space for trucks A lack of reciprocity between states in inspecting trucks, Lack of alternate routes for large trucks which results in repeated safety inspections of the same Lack of available and secure truck parking. vehicle in different states Restrictions on the use of drivers by labor agreements Local land use and zoning laws Operational Constraints State roadway funding mechanisms such as toll facilities Freight mobility constraints are not limited to physical A lack of harmonization between state size and weight infrastructure deficiencies. Operational characteristics of both regulations the transportation system and motor carriers' customer bases U.S. border crossings and other security-related restrictions also create freight mobility constraints. Motor carrier customers Route restrictions on longer combination vehicles frequently require pickup and delivery appointments during Access/parking restrictions near office and government peak travel periods, causing carriers to add more trucks and buildings drivers to maintain service levels and exacerbating congestion Hazmat route restrictions in already congested areas. Operational characteristics of the Central business district (CBD) truck restrictions transportation system that impose constraints may include Safety- and security-related policies that affect the avail- the following: ability of drivers.