30 ILCS 105/6c

All fees and other money received by the Division of Highways of the Department of Transportation shall, upon being paid into the State treasury, be placed in the Road Fund. After July 1, 1981 (the effective date of Public Act 81-1487) and until June 30, 2026, investment income which is attributable to the investment of moneys of the Road Fund shall be retained in the Road Fund. Beginning July 1, 2026, of the investment income which is attributable to the investment of moneys of the Road Fund, 90% shall be deposited into the Northern Illinois Transit Authority Capital Improvement Fund and 10% shall be deposited into the Downstate Mass Transportation Capital Improvement Fund.