Traffic Engineering

Traffic Lights Augusta
Traffic Engineering

Dennis E. Ellis
Traffic Engineereing Technician

Studies

The Traffic Engineering Division conducts various engineering studies in response to citizens or governmental requests. These requests may be for a new traffic signal, all- way stop control for an intersection, speed limit changes, changing the operation of an intersection's signals or any thing that may improve the safety and efficiency of our streets and highways.

The division also investigates complaints concerning sight obstructions caused by vegetation, signs or other obstacles and makes sure the problem is corrected.

TRAFFIC ENGINEERING REPORT (Sample)

LOCATION: Mike Padgett Hwy. (SR 56) at Tobacco Road

REQUESTED BY: A Citizen

REASON FOR REQUEST: To determine if protected left-turn phasing should be added for the east-west Tobacco Road approaches. The northbound approach on Hwy. 56 has a protected left-turn phase.

FINDINGS: Using guidelines contained in The Manual of Traffic Signal Design:

Volume:

Left-turn volume greater than 100VPH during peak hour(s)

A.M. Peak Hour-- EB LT-- 103 Vehicles
Noon Peak Hour -- EB LT -- 113 Vehicles
P. M. Peak Hour -- WBLT – 128 Vehicles
Left-Turn volume greater than 50 VPH when speed equals or exceeds 45 MPH.

M. Peak Hour -- EB LT -- 103 Vehicles; WB LT -- 40
Noon Peak Hour -- EB LT -- 86; WB LT -- 35
P.M. Peak Hour – EB LT – 113; WB LT – 128

Delay:

One left-turning vehicle delayed one cycle or more during one hour.

On September 23, l998, from 4:30 to 5:20 P. M., there were three cycles when four, WB left-turn vehicles did not clear and two cycles when two WB left-turn vehicles did not clear. Beginning at 5:20 P. M., each cycle had at least three WB left-turn vehicles unable to clear. The count ended at 5:30 P. M. However the queuing was getting worse.

Conclusion: Much of the P.M. delay for the WB, left-turn approach is caused by logging trucks and tractor-trailers using this intersection. There is a small number of EB-WB left-turn accidents annually. However, the delay experienced by EB-WB left-turning vehicles is unacceptable given the low volume of EB-WB approach traffic.

Recommendation: Installation of Eastbound-Westbound protected left-turn phasing.

Dennis Ellis
Traffic Engineering Technician