Good question! They did that on Mustang Rd between SW 44th & SW 29th St. Other addns usually just get a turn in or turn out area off the road itself to assist flow.
ETA: The road widening on Mustang Rd was probably required since the road has curbing. Not so on SHWY 92. No widening anywhere along it either except soon to be at the Reno intersection it looks like.