As you head south on Highway 15 in Oklahoma, you’ll be driving through some of the most scenic parts of the state. The drive is beautiful but dangerous.
The Oklahoma Department of Transportation (ODOT) noticed that the roadside fatality rate on State Highway 15 was four times the statewide average. They knew they had to do something about it, so ODOT added the roadway to their plan to invest in crucial state highways and awarded an engineering contract to Olsson.
Highway safety has long relied on drivers staying sober and following speed limits to minimize crashes. But Olsson and ODOT saw an opportunity to improve highway safety by including design elements that would help reduce the risk of collision.
The two existing lanes of this highway were 12′ wide with 2′ shoulder widths. The proposed project was to widen the shoulders to 8′, which would help make the highway safer by reducing accidents due to people leaving the roadway. It would also reduce rollovers by cutting down on steering overcorrections.
Olsson looked back at areas where there were a lot of accidents and identified the ones in proximity to slopes that make it difficult for a driver to regain control of their vehicle. This meant designing flatter slopes at several key locations.
Olsson recommended extending bridge culverts, so they are farther from the roadway. Olsson’s design criteria for highway restoration projects were not as stringent as those for new construction. So they used stricter standards to position the culvert headwalls.
Early on, looking at State Highway 15 data, we’re very hopeful. The overall collision rate has been reduced by 50% and there have been no fatal accidents.
