A Business Record analysis of state and local records found that Interstate 235 traffic in western Des Moines and West Des Moines already has exceeded what engineers predicted for 2020 when the freeway was planned in 1999.

This is a big deal because the freeway crosses through the heart of Des Moines, delivering both workers and goods to the city’s growing downtown area and serving suburbs that are among the fastest-growing cities in the state.

Greater Des Moines is expected to grow to 750,000 residents by 2050, up 56 percent from 480,000 in 2010.

The latest version of the freeway, a $430 million project finished in 2007, is smaller than engineers wanted. They warned, as construction approached in 2001, that the freeway would have capacity problems within 13 years, and that local leaders would have to look to car pools, bus service and traffic management to keep freeway traffic moving.

Serious rush hour congestion arrived by 2012, and it’s now passing the 2020 projections. Now, state and local officials are looking to pace traffic with on-ramp signals, calling for better mass transit, and debating a new system that would vary speed limits displayed on digital signs.