Illinois' investment in maintaining roads and bridges drops dramatically in the coming year under a plan Gov. Bruce Rauner's administration released Thursday.

The Illinois Department of Transportation warns that without new revenue, the mileage of acceptable highways in Illinois could drop from 83 percent today to 62 percent by 2021.

The five-year road plan released by the Illinois Department of Transportation shows a sharp drop off in spending on roads and bridges in the budget year that begins July 1. The state plans to spend $1.85 billion next year. But the five-year total is $8.4 billion — which means annual spending could fall as low as $1.4 billion.

Rauner and lawmakers face a deficit of as much as $6 billion next year.

Fontanis, ThinkStock