Understanding Traffic Indexes

Please note that the indices in this section are based on user-contributed data. Our goal is to provide a platform where individuals can share their experiences and perceptions of traffic conditions in their respective cities.

These indices rely on data provided by users and may not reflect official or comprehensive traffic statistics. However, they offer valuable insights into overall traffic conditions and commuting experiences in different locations. We encourage you to use these indices as a general reference and, when possible, complement them with other reliable sources for a more comprehensive understanding of traffic conditions.

Traffic Index is a composite measure that considers factors such as commute time, dissatisfaction with time spent in traffic, CO₂ emissions, and overall traffic system inefficiencies. It provides insights into the overall traffic conditions in a city.

Time Index represents the average one-way daily commute time required in minutes. It provides an indication of the time it takes to travel from one place to another within a city.

Time Exp. Index is an estimation of dissatisfaction due to long commute times, assuming that dissatisfaction increases exponentially (with each minute) after a one-way commute time is longer than 25 minutes.

Inefficiency Index estimates inefficiencies within a city's traffic system. A High inefficiency score typically indicates a preference for private car use over public transportation or excessively long commutes. It can be used as a traffic component measurement in economic analyses.

CO₂ Emission Index estimates CO₂ emissions attributable to daily commute by passenger, measured in grams for the round trip. To calculate an average CO₂ emission in grams for one-way commute, divide this value by 2.

How the Indices Are Calculated

The formulas used to calculate these indices are subject to change and are based on complex empirical models. The current implementation, written in Java, is as follows:

  protected void calculateIndex() {
    index = new TrafficIndex();
    index.time = overall.getTimeOverall();
    double tooMuchTime = 0.0;
    if (index.time > 25.0) {
      tooMuchTime = index.time - 25;
    }
    index.timeExp = index.time + Math.pow(tooMuchTime, Math.E);
    double co2 = 0.0;
    co2 += overall.time_bus * 20.0; // bus produces 20g of CO2 per minute (for each passenger)
    co2 += overall.time_driving * 133.0; // car produces 133g of CO2 per minute (assumes only driver)
    co2 += overall.time_train * 10.0; // train produces 10g of CO2 per minute (for each passenger)
    co2 += overall.time_tram * 15.0; // tram produces 15g of CO2 per minute (for each passenger)
    co2 += overall.time_other * 10.0; // other produces 10g of CO2 per minute
    co2 += overall.time_motorbike * 80.0; // motorbike produces 80g of CO2 per minute
    index.co2 = 2 * co2; 

    index.main = index.time + Math.sqrt(index.timeExp) + Math.sqrt(index.co2) + Math.sqrt(index.inefficiency);
}

Based on Arbor Environmental Alliance data, a single tree absorbs 21.77kg (48 lb) of CO₂ annually. To estimate the number of trees needed to offset commute-related CO₂, we assume 240 commuting days per year.

In Java code:

    double co2CommuteConsumptionYearly = 240 * index.co2;
    double treesNeededForCommute = (co2CommuteConsumptionYearly / 1000) / 21.77;  //each tree absorbs about 21.77kg of CO2