So far in this discussion on traffic control planning, I’ve pointed out why getting the plan in place is critical to a smoothly functioning project. Last time, I outlined the components of what a plan should include.
Now, in perhaps what most people see as the most visible part of a road construction project, I’d like to go over traffic control devices such as barricades. Each of these listed below has a specific purpose. It’s also important that everyone involved in a project, from a county engineer to the contractor, agree on where and when they should be used. Here’s what is normally available for road construction projects:
Used only when workers are on the job site. Use should be limited to a two-mile stretch of roadway, maximum. The standard cone should be 36 inches in height and 12 pounds.
- Tubular markers
Used on lower speed, narrow roads, during daylight hours only. A tubular marker shall be 36 inches in height and 4 inches in diameter.
Highly visible devices that have good target value. They give the appearance of being formidable obstacles and command the respect of motorists. A warning light is included with the drum. Drums shall be 36 inches in height and 18 inches in diameter.
- Vertical panels
These may be used for channelization and are particularly appropriate for traffic separation in locations where lateral space is restricted. The panel shall be 36 inches in height and a minimum of 12 inches from the ground. The panel shall be 12 inches wide
- Type I Barricade
This barricade has one horizontal retro-reflective rail. The markings should slope downward at a 45 degree angle toward the direction of traffic. The barricade shall be 36 inches in height and 36 inches in width. The rail shall be 12 inches in height.
- Type II Barricade
This has two horizontal retro-reflective rails. The ballast shall not be placed on the top rails of any striped rails or higher than 13 inches above the driving surface. The barricade shall be 36 inches in height and 24 inches wide. The rails shall be 8 inches in height.
- Type III Barricade
This barricade has three horizontal retro-reflective rails. Road closure signs may be mounted on Type III barricades. The barricade shall be 6 feet wide and the rails shall be 8 inches in height.
- Direction Indicator Barricade (Type D1)
The Type D1 has an arrow on the top panel and a standard horizontal retro-reflective rail on the bottom rung. It may be used in tapers and transitions and shall be used in series. The barricade shall be 36 inches in height and 24 inches in width. The arrow panel shall be 12 inches in height and the rail shall be 8 inches in height.
Needless to say, barricades are a critical part of road projects, simply because they keep motorists away from where they shouldn’t be. In my next post, as we continue our discussion about traffic control planning, we’ll go over traffic control zones, what they are and how they’re used.