Mechanical ventilation of tunnels is costly because of the initial installation and the continued maintenance and operation. However, at some tunnel length corresponding to a particular altitude, traffic configuration and topography there is a need for this forced ventilation. This study was undertaken to help determine the pollution concentration in existing tunnels in Colorado, and predict the length of tunnels which will need mechanical ventilation....

For many years the Colorado Division of Highways has been testing and evaluating different types of paint, glass beads, or other types of traffic marking materials as they come on the market.

Air pollution is a matter of concern everywhere, but at high altitudes it may have more significance because of the difficulty that some people have breathing rarefied air. Much of the construction in Western states is above the 6,000 foot level, and highways have been constructed above the 14,000 foot level. The results of tests for carbon monoxide, hydrocarbons, nitrogen oxides and particulates at construction sites in Colorado are presented in...

This particular Colorado study was initiated to gather and analyze facts on the performance of embankments constructed without moisture and/or density control, and to draw specific conclusions which might assist designers of future roadway embankments.