This report is an Informational Guide for highway agencies on the use of low-cost improvements to alleviate operational problems on two-lane highways. The Guide addresses both passing and turning improvements that can be constructed for a lower cost than construction of a continuous four-lane highway. The passing improvements presented in the Guide include passing lanes, climbing lanes, short four-lane sections, turnouts, shoulder driving, and shoulder use sections. The turning improvements included are intersection turn lanes, shoulder bypass lanes, and two-way left-turn lanes. Design and traffic control guidelines presented for these improvements include location and configuration guidelines, geometric design criteria, recommended signing and marking practices, and operational and safety effectiveness estimates.