The Concept of Effective Speed
How fast are we when moving from A to B? We are used to talk about regular speed which is distance divided by time. But what about the time spent waiting for the bus or the time spent at work to earn the money to pay all the costs created by the particular mode of transport? Different from regular speed, Effective Speed or Social Speed takes these aspects into account. Effective Speed can be defined by total distance travelled divided by the total time devoted to the mode of transport. Eric Morfa Morales writes about the outcomes of a study on Effective Speed made in Mossoro City, Brazil.
Effective Speed Turns Speed Concept Upside Down
Our work compares the regular speed with Effective Speed for different modes of transport in relation of monthly wage. Using data collected from 22 Commuter Challenges made between 2012-2014 we found that average speed in the streets for walking, cycling, public transport, motorcycle and car were: 5km/h; 16km/h; 8km/h; 26km/h and 28km/h. Looking these one might say that motorcycle and car are the fastest way to move in a city but the concept of Effective Speed shows something different.
Effective Speed was estimated only for workers. Workers Wage National Data Base was divided in 10 levels, from level 1 (U$75/month) to level 10 (>U$9,000.00/month). Effective Speed was calculated for every level for different modes of transport. The result shows that at level 1 workers can only buy 3 different types of trips: walking, cycling and public transport. Walking is working free, people who work have to discount 0.55hs of his 8hs working day to buy bicycle trips and 6.56hs for public transport, applying these working times plus the time to buy a trip by mode we find Effective Speed for each transport mode: 5km/h(walking), 9.12km/h (cycling) and 1,44km/h (public transport). At level 1 laborers cannot afford other modes of transport.
Using this methodology we find that till level 7 (U$39,000.00/annual) or for 95% of workers in Brazil the most Effective Speed in a medium city is cycling despite the low investment made in this mode of transport. If applied, Effective Speed could reorient public investments towards more equitable transport modes.
Collecting Qualitative Data with Commuter Challenges
In order to estimate the effective speed in Mossoro city, Brazil, we promoted several Commuter Challenges in the years of 2012, 2013 and 2014. Commuter Challenges aim to assess the effectiveness of different modes of transport such as walking, cycling, motorcycle, car, public transport etc. regarding aspects as travel time, costs, emission of pollutants and so on. Using a map of the city divided in several quadrants we designed this Commuter Challenge to have random origin or destinations points.
The point of origin and destination were the centre of this quadrant, to determine these quadrants we wrote in piece of papers letters and numbers correspondents to the lines drawn on the map, put all theses in two bags, one for numbers and other for letters. To choose the quadrant a student had to get two pieces of paper inside the bags one for numbers another one for the letters.
In a commuter challenge all participants go to the origin point. When everybody is there someone explains that it is an exercise and not a race and they must behave as they normally do and obey the law while they’re driving, walking, biking etc. After explanations everyone must start their chronometers and the exercise begins. The first one to arrive at the destination point takes his/her time. After all had reached the destination point someone collects all data (travel time, money spent etc.) and prepares a report which will give an idea about every trip made.
We have made 24 Commuter Challenges so far, they were done at peak and non peak hours, all of them were made during week days.
The average speed and standard deviation per mode collected in these Commuter Challenges can be seen here:
As one can see, public transport (buses) in Mossoro City are very slow because the waiting time (headway) between them is about 1 hour, the waiting time plus walking to the bus stop and walking to the destination point increases the travel time abruptly, inside the bus the speed is about 16km/h, only.
Because we had access to the Workers National Data Base our study estimated effective speed only for workers. According to Brazilian National Data Base, Mossoro City presents a monthly wage dived in ten levels, as one can see it’s a very poor city. Almost 86% of the work force has a monthly wage of about $ 626,09 US-Dollar.
To estimate the effective speed we choose to compare different modes of transport and because we’re a car society we also estimate Effective Speed for different classes of cars. Taking different modes of transport and different types of cars we calculated fix and variable costs for each mode.
Considering the monthly wage, which was transformed in working minutes to buy a trip by mode, the average distance travelled by worker and the total cost by mode we have: effective speed by wage. Bicycle is the most effective way to get around in Mossoro till the level 7 (US$3,130.00/month), motorcycle (100 cc) will most effective over this wage.
About the Author:
Eric Amaral Ferreira
I had worked for years ago at ITDP (www.itdp.org) promoting sustainable transport in Brazil, Colombia, México and Indonesia. Before I worked for ITDP I worked 5 years at Metropolitan Transport Authority in Curitiba designing and implementing public transport. When I became professor at Federal University I invited some students to make researches focused mainly in bike, walk, and public transport. One of the outcomes of this study group was the Effective Speedy, nowadays we´re in 10 people.