Disadvantages
There are also some disadvantages to using frontage roads. When frontage roads are used without controlling the access to the main road, at every intersection an intersecting road runs from one side to another the number of conflict points increases one fold for each frontage road. This is because each frontage road is itself another intersection. Three examples are US 190 in East Baton Rouge Parish, Louisiana; LA 1 in West Baton Rouge Parish, Louisiana; and Palatine Road in Cook County, Illinois. Frontage roads also obviously take up large amounts of space and cost more. A highway with frontage roads is hard for pedestrians to cross, given the increased width of road, and vehicles in the central carriageways driving at high speeds.
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