This project in Manitoba, Canada, developed a single-slope concrete barrier system with a height of 1,250 mm and a base width of no more than 600 mm. Configurations for bridge rail, roadside, and median barrier applications were developed and optimized to minimize installation costs while satisfying the AASHTO Manual for Assessing Safety Hardware (MASH) Test Level 5 performance standards. Additionally, a bridge deck was developed for the overhang portion of the deck supporting the bridge rail. To evaluate the new barrier system, a 45.7-m-long section of the bridge rail was constructed on a simulated bridge deck and subjected to a full-scale crash test according to MASH Test 5-12. During the test, the 36,000-kg vehicle was safely redirected with minimal roll to the cab and trailer. Damage to the barrier and deck was minor, consisting of concrete gouging, hairline cracks, and some spalling to the top of the barrier. Thus, the Manitoba constrained width tall wall was deemed crashworthy to MASH Test Level 5 standards.