The evolution of intelligent transportation systems has experienced in a very small window of time, the interactive communication of smartphones, more efficient data collection and tolling technologies, the better use of detection devices for warning systems as well as for transportation planning, and the early onset of market implementation of autonomous vehicles. Going back to core visceral beliefs, it is still the driver and the resulting decisions to the current transportation experience over the road that impact all of our safety. Trucking transportation best illustrates this experience.
In the past, we’ve blogged the proper use and application of Variable Speed Limit Signs on U.S. highways as it pertains to use relative to either traffic or weather conditions. Highlighted were typical designs and regulations with options regulatory agencies employ in color and size of the overall sign, both for the static and the LED aspect of the sign. In the majority of applications however, typical 12 or 18” characters employed fall short of MUTCD full compliance.
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.
Defining the right type of sign for a specific project can be challenging. There are many different reasons and criteria that effect the choice of one product versus another. Designing a Variable Message Sign to solve a road safety challenge requires a thorough process and defined methodology - it is important to ask the right questions.
On one side, choosing the most advanced sign that can display anything, in any color, at any time is the easiest and most unlimited option. However, this often creates other challenges like power issues, monitoring complexity, and exorbitant costs for simple applications.
On the other side, very simple and cheap solutions exists, such as static signs with flashing beacons. Although, this can also have many disadvantages and does not solve most of the problems discussed in one of our previous blogs.
Throughout several blogs, we discussed the benefits of Blank Out Signs (BOS) and Lane Control Signs, and compared their technology against Dynamic Message Signs (DMS) and other types of signs. In this blog, we want to discuss the cost benefits of using Blank Out Signs and Lane Control Signs.
We recently published a blog about the 5 Display Properties Defined by NEMA TS4 and are continuing with our series referencing these specifications for Dynamic Message Signs (DMS). This installment will examine the Environmental Requirements described in Section 2 of NEMA TS4 that establishes the limits of operational conditions in which the DMS must perform. They are also intended to make sure the DMS is delivered in good condition.
The NEMA TS4 Hardware Standards for Dynamic Message Signs (DMS) with NTCIP Requirements is a product of the NEMA 3-TS, Transportation Management Systems and Associated Control Devices Section. It is intended to provide the user a safe, dependable, functional and easily maintained Dynamic Message Sign. To this end, the standard provides the minimum hardware and functional characteristics of electronically controlled DMS used for displaying messages to travelers.
Static MUTCD traffic signs are often used to warn drivers of specific conditions or potential danger on the roadway, and in many applications are equipped with flashing beacons to provide alert capability for passing motorists. However, many of these signs do not efficiently convey information necessary for drivers to fully understand the circumstances and actions to take to avoid danger.
Here below is a series of examples with comments related to the efficiency of the message:
When designing ITS systems intended to convey critical messaging to drivers, transportation agencies must consider the requirements for each deployment, and make choices regarding more versatile, full matrix dynamic message signs versus more affordable blank out signs with limited messaging. Often blank out signs can provide all the messaging functionality needed at a fraction of the cost of full size DMS, and do not require advanced communication networks or other infrastructure required by signs with full messaging capability.