State DOT highway Intelligent Transportation Systems (ITS) are progressively capitalizing on comprehensive Variable Speed Limit (VSL) designs. As a more advanced and timely safety warning system, changing the speed limit based on weather or traffic conditions in focused locations offers more precise warning to stretches of especially vulnerable roadways. In often non-negotiable winter road conditions, unreliably slippery roadways require more precise, distinctly locational, lower speed limit advisories. Ideal weather conditions of summer, not so much. Variable speed limit systems are continually proven ITS safety devices in such states as New Hampshire, Wyoming, Minnesota, and Utah. The VSL Subscribers list continues to climb as a cost effective, dynamic messaging system, in particular with rural locations.
VSLs foster opportunity for DOT’s to utilize accurate placement for both regulatory and warning applications. Serving as warning signs with amber colored characters in particularly hazardous locations, the dynamic aspect of posting variable speed limits or for that matter, blanked out signs, creates a positive and engaging interface with the driving public. Applied as a regulatory sign, VSL’s with white characters bring into play stricter standards with law enforcement options. Excising proper design criteria, these signs can meet MUTCD standards for lettering in sizes 12 to 18 inches.