12/07/2023

4 min read

Before-after analysis report structure

**TrafficScope: Before-after analysis, Benefits at a glance, Traffic delay matrix **

Each cell on the matrix shows travel time reduction and traffic delay benefit for each hour of the week. On this matrix for Traffic Delay, one can immediately see that the implemented improvement measures are overall effective: the majority of cells are blue, which means there is some gain.

Statistics on the right provide averages and extremums for gains and losses, as well Av. Traffic Delays values for before and after periods.

Matrix of Benefits allows identification of problematic time slots, where new system caused degradation rather than improvement. These slots are red, with the brightest - and the worst - on Friday afternoon. TrafficScope provide other similar matrixes for travel time reduction and for cumulative traffic delay. For all calculations Median traffic flow speed is used.

Glossary: Travel time reduction = Travel Time “Before’ – Travel Time ‘After’ [s/veh] Traffic delay = Travel Time at Current Speed – Travel Time at Free Flow Speed [s or s/veh]* Cumulative Traffic Delay = Traffic delay * Traffic Volume [veh*h]

*Physically traffic delay is measured in seconds, but often it is denoted in s/veh since each veh experience this delay. To ensure accuracy, Ticon uses median traffic flow speed for this calculation.

Trafficscope: Before-after analysis, Benefits at a glance, Traffic delay along the corridor

The graph can be built for the day or any specific period of time. This one reflects Friday afternoon that was identified as problematic area from traffic delay benefit matrix (see previous slide). At each problematic zone traffic delay before (blue line) is below traffic delay after (green line). Values of traffic delay in seconds are depict on the vertical axes.

Horizontal axes shows the corridor of interest, which in this example is 13638 ft. long. Street names marked below the axis for better identification of each intersection’s impact on total traffic delay.

The graphs of this type can be ordered in advance to improvements implementation, for ‘before’ period only, in order to optimize the choice or order of areas/corridors/intersections to be improved. It is highly recommended to do preliminary study of this kind.

Coming soon: Cumulative traffic delay along the corridor This graph will visualize the most important sections from the point of total time losses by drivers and passengers. These sections should be addressed first to maximize cost benefits from ITS implementation.

Trafficscope: Before-after analysis, Performance analysis, Traffic speed and traffic volume along the corridor

The graph can be built for the day or any specific period of time. This one averaging one day (24h).

Horizontal axes depicts the corridor of interest with intersections’ names marked below the axis. Left vertical axes shows the values of traffic flow speed [mph] and the right one – traffic flow volume [veh/h], averaged for 24 h.

Broadly speaking, the goal of each improvement – to increase capacity, i.e. traffic volume or to decrease traffic delay or to do both. So simultaneous comparison of speed and volumes parameters allows the understanding of the improvement efficiency along the corridor.

The yellow curve represents speed ‘before’ and the red one – speed ‘after’, so the distance between them illustrates changes is traffic delay. In case of positive changes the red curve will always be located above the yellow one. Yellow columns represent traffic volume, carried by the segment ‘before’, and red ones – ‘after’. Significant difference between columns heights indicates serious changes in segment capacity. On the contrary, small difference suggests no changes in demands/flows and can be attributed to usual volatility of traffic patterns.

The graphs of this type can be ordered in advance to improvements implementation, for ‘before’ period only, in order to optimize the choice or order of areas/corridors/intersections to be improved. It is highly recommended to do preliminary study of this kind.

It is rational to suggest customer to order Speed/Volume graphs averaged not only for 24h, but also for ‘active period’ or peak intervals

TrafficScope: Before-after analysis, Performance analysis, Traffic speed and traffic volume changes for each section

The graph depicts changes in traffic flow speed and traffic flow volume for the road section for a day, i.e. for 24h.

Left vertical axes shows the values of traffic flow speed [mph] and the right one – traffic flow volume [veh/h], averaged for 15 min or 1 h bin, depending on customers order. Same as on previous graph, the yellow curve represents speed ‘before’ and the red one – speed ‘after’, yellow columns represent traffic volume, carried by the section ‘before’, and red ones – ‘after’.

The graph allows detailed analysis of traffic patterns over time. From multi-years experience we know that each day of the week is different, so it is strongly recommended to order seven of these graphs for each section of interest. Weekdays/Weekends graphs are also available though.

The graphs of this type can be ordered in advance to improvements implementation, for ‘before’ period only, in order to optimize the choice or order of areas/corridors/intersections to be improved. It is highly recommended to do preliminary study of this kind.

The graph is supported by EXCEL file, which can be used as ‘approach’ data for modelling in Synchro, T7F or other traffic optimization software.

TrafficScope: Before-after analysis, Performance analysis, Traffic speed and traffic volume heat maps for the corridor

This heat map, as one may say, incorporates the information from ‘sections’ graphs introduced on previous slide and visualize traffic speed and traffic volume distribution regularities for all sections along the corridor. Each cell reflects the value of the corresponding variable for certain period of time specified on vertical access and certain section (indicated on horizontal axis). The heat map can be built for the day or any specific period of time, and consists of two parts: volume (above) and speed (below).

The graph allows detailed analysis of traffic patterns along the corridor of interest over time. The user can see how traffic flow changes along the corridor and simultaneously over time. It is interesting to note that traffic volume increase not necessarily coincides with the periods of speed decrease (see graph section by dotted line for an example).

From multi-years experience we know that each day of the week is different, so it is strongly recommended to order seven of these graphs. Weekdays/Weekends graphs are also available though.

The graph is supported by EXCEL file, which can be used for simulation modelling or for 3D plotting.

TrafficScope: Before-after analysis, Performance analysis, Traffic speed and traffic volume heat maps for the corridor

TrafficScope provides saturation heat map, where each cell represents saturation degree for each approach, for every 15-minute bin.

There are for approaches at this intersection: West, East, North and South. Fifth line indicated total saturation degree for the intersection. For this example total saturation degree (last row) is below 80% for the most of time slots, which means this particular intersection had a potential of performance increase. Evaluation of the horizon of possible improvements is the main purpose of this heat map. Also this heat map is helpful for choosing the strategy for signal timing management.

For example, time slot appointed by red arrow is characterized by almost 100% saturation. Consequently, it is not wise to expect notable improvement at this period of time by improving of the direct control. Instead, it is worth to explore the possibilities of traffic diverting or temporal restriction/limitation. At the same time there are not many oversaturated time slots. So further upgrading of signal timing does make a lot of sense. At least it is very possible to expect more productivity than from previous improvement, which was calculated by Trafficscope as 3.72% (number n red). Usually traffic demand in conflict directions changes rapidly, and this is the case for current example too. So, when formulating a task for signal timing optimization it is desirable to stress the need of having individual timing tables for most of the time slots.

TrafficScope: Recommended workflow

TrafficScope makes the evaluation of the efficiency of the implemented measures quick, easy and affordable. Now this is no need to pay tens of thousands for couple miles ‘before and after’ study. Even more important that Trafficscope delivers ‘before-after evaluation with 100% temporal and spatial coverage, which dramatically decrease the possibility of wrong decisions based on misleading information.

All above allows to advance the strategy of ITS implementation and: (1) perform one improvement at a time; (3) evaluate each improvement separately; (3) speed up global implementation and simultaneously use ‘pilot projects’ approach; (4) increase tune-ups efficiency by ‘iteration’ approach.

**TrafficScope: Forensic capabilities **

TrafficScope opens radically new opportunities for mobility improvement planning. It is based on the analysis of measures that had previously been implemented on the road network. For most areas, Trafficscope is able to build reports for any period of time during the past 10 years. In other words, it is possible to conduct before-after analysis of previous activities, and see what the effect of each one was.

This "analysis of mistakes" will be undoubtedly better suited to select the technologies for the further changes, as well as build certain ranking records.