Left‐Turn Adjustment Factor for Permitted Phasing

The left-turn adjustment factor, as introduced in the 1985 Highway Capacity Manual, for opposed left-turns at a signalized intersection is discussed. The special case involving an exclusive left-turn lane without a separate phase is examined. It is shown that the procedure presented in the manual can be significantly simplified for this situation. A comparison between the left-turn adjustment factor from the new manual and from the procedures of the Interim Materials on Highway Capacity (1980) is presented.