 For more than 30 years, W-beam guardrails have been one of the most common types of guardrails used on our nation's roadways. Strong post W-beam guardrails are versatile systems that can be used in many types of situations. Every state uses some type of W-beam guardrail system in its state standards. The typical strong post guardrail consists of a 10 or 12 gauge W-beam. You can use 6x9 steel posts, or 6x8 inch wood posts and block outs, and an appropriate terminal. Strong post W-beam guardrails have been shown to be effective for small cars, mid-sized cars, and large cars. Unfortunately these systems are not nearly as effective for larger vehicles like the school bus. The center of gravity of the bus is much higher than the barrier. Instead of being redirected by the barrier, the bus simply rolls over onto it. Containing larger vehicles like school buses, inter-city buses, single unit trucks, and tractor trailer trucks has become increasingly important on some roadways. A need for higher performance guardrails that would safely redirect both typical passenger cars as well as trucks and buses was the motivation behind the development of the Thrive-Beam Guardrails. Thrive-Beam is similar to W-beam, but there are several differences. The W-beam has two corrugations. The Thrive-Beam has three. W-beam is 12 and a quarter inches deep. But Thrive-Beam is 20 inches deep because of the extra corrugation. The standard Thrive-Beam barrier, called the G9 Guardrail in the Roadside Design Guide, was developed to improve the performance of the strong post guardrail systems. Normally, the top of the W-beam on a typical strong post system is 27 inches above the ground. The top of the Thrive-Beam can be placed 32 inches above the ground because it is 8 inches deeper. The G9 system extends 3 inches lower and 5 inches higher than the normal G4 W-beam Guardrail. The higher mounting height of the Thrive-Beam was expected to make the system more effective than the W-beam in collisions with large vehicles. Here we see some of the results of that testing. Like W-beam systems, the Thrive-Beam Guardrail performs well in impacts with typical passenger cars. Unfortunately, the G9 Guardrail performed little better than the strong post W-beam Guardrail in this school bus collision. The bus still rolled over. This performance was not at all acceptable. The modified Thrive-Beam was developed specifically to provide better performance in large vehicle impacts while also performing well for passenger vehicles. The primary difference between the modified and the standard Thrive-Beam systems is the shape of the blockout. The purpose of Guardrail blockouts is to keep the vehicle wheels from contacting the Guardrail post. The modified Thrive-Beam blockout is much deeper than the typical blockout and it has a unique notch at the bottom. During an impact, this notch closes up causing the Thrive-Beam to remain nearly vertical as the post rotates in the soil. The modified Thrive-Beam Guardrail, while performing well in large and small car tests, provides drastically improved performance with larger vehicles like this school bus, as well as this 32,000 pound coach bus. Even after this severe test, this bus was still operational. These crash tests show the modified Thrive-Beam can contain and redirect a much wider range of vehicles than either the standard Thrive-Beam or W-Beam Guardrail systems. The modified Thrive-Beam will safely contain and redirect cars weighing less than 2000 pounds, as well as large coach buses weighing more than 32,000 pounds. Using safe crash-tested terminals and transitions is as important with the modified Thrive-Beam as any other Guardrail system. Any standard W-Beam terminal can be used as an in-treatment by using a transition W-Beam element to splice the Thrive-Beam to a W-Beam. Some accidents with Guardrails result in spearing and overturning. The chance of these types of accidents can be greatly reduced by using crash-tested terminals and transitions. Once the transition to a W-Beam is made, a breakaway cable terminal, CAT, ET2000, or any other W-Beam terminal can be used. This same transition element can be used to provide transitions to upstream and downstream W-Beam Guardrails and bridge rails. The sentry Guardrail terminal can be attached directly to the modified Thrive-Beam since it uses Thrive-Beam fender panels. Improved performance alone is not adequate justification for spending more money on roadside hardware. Highway departments always have many needs and too few resources. In several demonstration projects, the modified Thrive-Beam system costs between $25 and $30 per linear foot. Only a few dollars more per foot than the standard Thrive-Beam barrier while offering substantially better performance. This cost will probably decrease as the modified Thrive-Beam becomes a more popular alternative. If there's a good chance of a larger vehicle collision, the reduction in maintenance cost may be significant. In this test, 156 feet of W-Beam Guardrail were destroyed and would need to be completely replaced. The cost of repairing this damaged Guardrail would be about $1900. The same impact conditions with the modified Thrive-Beam resulted in damage to only 50 feet of Guardrail. The cost to repair the Guardrail after this collision would be less than $1200, $700 less than the repair cost for the W-Beam Guardrail. Many of the posts were not seriously damaged and could probably be reused, resulting in even greater savings. The modified Thrive-Beam Guardrail can also tolerate many nuisance hits without any adverse effect on the system's performance. This collision with a small car only bent six of the blockout tabs and displaced the posts a little more than one inch. The bent tabs were repaired using an automobile bumper jack and hammer. For sites where accidents occur frequently, the reduced maintenance cost of the modified Thrive-Beam will often offset the higher installation cost. The modified Thrive-Beam Guardrail can be integrated into standards that already make use of a strong post W-Beam Guardrail system. It is certainly not appropriate for every location where a W-Beam Guardrail might be used. But for locations with significant truck traffic or locations that are frequently struck, the reduction in maintenance cost and the improved performance make the modified Thrive-Beam an attractive alternative to traditional W-Beam Guardrails.