Prefeasibility Access Road Design-Revised
9
Upgraded Safety Design Requirements
The safety of a public roadway is the most important factor in its design. A roadway
must provide a surface wide enough to handle the traffic that will use it. Horizontal
curves must be designed to provide safe change in direction without leaving the
proper lane of travel, or leaving the roadway entirely. Vertical curves need to be set
flat enough to provide proper sight distance to allow time to make decisions and
avoid hazards that may be present in a vehicle’s path. Grades need to be considered
to make a road traversable in slick conditions such as ice and rain. Grade should be
gentle enough to allow heavy loads to maintain a safe speed downhill without loss
of control or brake failure. Intersections need to provide a path of travel large
enough to allow the longest planned vehicles to make right hand turns without
encroaching into the path of oncoming cars. There also needs to be sight distance
available to make safe decisions on when to enter the roadway from the
intersection. The typical sections on
Exhibit D-1 to Exhibit D-5 show these upgraded
safety features which will enhance the safety of the road.
