ABOUT AUTOJ

AutoJ (Automated Junction analysis) is a program which simulates and optimizes intersection design for three periods (typically the AM, PM and off-peak) at a time. While intended for use by the traffic professional, AutoJ is simple enough to be used by anyone regardless of qualification or experience. 

It is exceptionally easy to use. All that is required for an accurate assessment of any intersection is a traffic count and the number of lanes on each approach. The program has built-in defaults for all other input at a typical urban intersection which can be overwritten by the user. 

AutoJ will provide:

• The performance of every potential intersection control  (two-way stops, yields, all-way stops, roundabouts and 21 leading, lagging or split, two, three and four stage traffic signals);
• Optimized signal timings including timing diagrams and green/cycle ratios for each period;
• The volume, volume to capacity ratio, delay, queue length and level of service for vehicles and pedestrians for each period and for every movement, approach and intersection as a whole;
• A performance index indicating the best as well as relative performance of each of 25 possible intersection controls.

It is anticipated that it will mainly be used for traffic impact assessments and timing traffic signals. 

For a full list of uses, see the Optional Uses tab below.

For an example see the Example tab.

For technical information download the free User Manual, Technical Manual and / or how AutoJ was developed from international best practice in capacity, delay, queue and level of service calculations.

It is expected AutoJ will primarily be used for traffic impact assessments and signal timing designs, but can be used to undertake any of the following:

Analysis and comparison of all forms of intersection control;

Simulating any Control Device;

Identifying and recommending the optimal Intersection Control Device (ICD);

Optimizing an intersection design;

Exploring user generated alternatives;

To input and analyse traffic counts, including:

• quarter or hourly volumes
• buses and heavy vehicles, weighted as required
• pedestrians and cyclists
• future traffic growth (or decline)
• new development traffic, and
• printing in a user friendly format;

To record and analyse geometric design for each approach, including:

• lane marking options
• auxiliary turning lane length requirements 
• lane length adequacy
• median width
• approach speed
• grade
• right turning in gaps (allowed or not)
• left turn slip roads (yield or freely enter downstream lane)
• clearance distances for vehicles and pedestrians
• pedestrian heads (provided or not);

To test traffic signal design including:

• event table options;
• cycle times (separately for two, three or four stage signals);
• minimum greens, yellows and all-reds for main, leading, lagging and pedestrian phases;
• offsets and co-ordination efficiency;
• optimise traffic signal timings (which is what AutoJ was originally built to do);

To compare 25 types of intersection control devices simultaneously for three periods at a time, including:

• two-way Stop streets (“main” road not stopped)
• yield controlled or free flowing slip lanes
• all-way Stop streets
• roundabouts and mini-circles
• two stage traffic signals
• three stage signals, lagging and leading (six possibilities)
• four stage signals, lagging, leading and combinations (nine possibilities)
• separate split stage signals and combinations (five possibilities)
• user generated options;

To calculate signal timing intervals, including:

• 21 staging options
• main phase greens
• yellow and all-red intervals
• pedestrian crossing times (green man and flashing red man)
• pre-timed or actuated minimums and maximums
• with a graphical display of the chosen settings (staging diagram);

To simulate performance (using measures of effectiveness) of each movement and totals, including:

• green to cycle (g/c) ratios
• volume to capacity (V/C) ratios
• average delay
• queue and total delay
• level of service (two measures)
• performance index;

To undertake specific investigations, including:

• warrants for traffic signals, roundabouts and stops
• traffic impact assessments
• the effect of growth and changing traffic patterns
• comparing existing and proposed signal settings
• performance index (PI)* comparisons
• giving priority to selected movements, such as Bus Rapid Transit (BRT)
• analysing up to three periods at a time
• obtaining a user friendly visual display of inputted data and results
• inputting user defined settings
• research, including testing imaginary options.

DR JOHN SAMPSON (Pr Eng, FSAAE, FSAICE) is the founder of AutoJ Traffic. 

Dr Sampson has the following qualifications

• BSc Civil Engineering (Wits)
• MSc Transportation Engineering (California, Berkeley)
• BCom (UNISA) 
• PhD (Wits)

His experience includes 

• Managing Director of TTT Africa
• Partner and Director of Jeffares & Green Consulting Engineers (now JG Afrika)
• Professor at the University of Pretoria
• Deputy City Engineer of City of Johannesburg
• Chairperson of the Board of Directors of the Road Traffic Management Corporation
• Director of the Road Traffic Infringement Agency
• Expert on Gauteng Transport Commission 
• Member of the Gauteng Integrated Transport Master Plan Steering Committee.