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How to Calculate and Minimise CO2 Emissions with Travel Time Data

by Christopher Hutchinson on Feb 23, 2021

TravelTime customers are often interested in using data to make better decisions about where to locate their offices, or to advise their own clients about the same issue.

One way to tackle this question is to use travel time data to calculate and compare the commute times for employees to different office locations.

For example, businesses may wish to minimise the average commute time for all employees or ensure that no employees have a commute time of more than a certain maximum value. With TravelTime, this analysis can be run for any mode of transport, providing a complete picture of the commutability of different offices.

Increasingly however, businesses are also looking to understand the potential CO2 emissions associated with employee commutes, and how this may differ between potential office locations and transport types.

Why look at employee commute emissions?

At the most fundamental level, calculating the CO2 impact of employee commutes to different potential office locations provides businesses with another data point to use in the evaluation process. And it is not an insignificant data point – according to a 2009 study by the US Department of Transportation, the average person in the US drives over 2,000 miles a year simply commuting.

By analysing the data for different offices and different modes of transport, businesses can reduce their environmental impact in two ways:

  1. Select office locations that minimise emissions based on the assumption that all employees will continue to commute by car, but with the shortest possible journeys

  2. Select office locations that are more accessible to employees using greener transport types, such as public transport, cycling and even walking

The benefits of using this data are numerous, but may include:

  • Meeting government or industry regulations
  • Attracting employees who place particular importance on environmental sustainability
  • Contributing to wider Corporate Social Responsibility initiatives

How to use TravelTime to promote greener commute methods

When considering office locations, the first way you can use TravelTime to manage emissions from employee commutes is to calculate the commute times for all modes of transport.

Being able to calculate this for all transport modes allows you to find potential opportunities for employees to replace their driving commute with a commute that instead uses public transport, cycling, or even walking.

For example, we calculated the table below using the Travel Time Matrix macro for Alteryx, which shows the different commute times (in seconds) for each employee to a potential new office location.

TravelTime commute time analysis

This commute time analysis shows, for example, that cycling could be a good option for Employee_1000, while for Employee_105 it might be that public transport can be used for their commute instead of driving.

How to use TravelTime to calculate and minimise emissions

While TravelTime does not provide CO2 emissions data directly, we do provide the underlying data that can easily form the basis of a CO2 emissions calculation – specifically, distance travelled.

For driving, the true distance can be returned as part of a Distance Matrix, while for public transport, the lat-longs of the returned route can be used to calculate the straight-line distances between the stops along the route.

Once the distances have been calculated, there is no one 'correct' way to calculate CO2 emissions, as there will be many factors involved such as type of car, driving conditions, etc. But below we outline one potential approach, using UK government data, that is already employed by a number of TravelTime clients.

  1. Download a document of conversion factors. These change year-on-year, but all historic years can be found here. The file to use is the full set for advanced users:
    Government conversion factors
  2. Open the sheet called ‘Business travel- land’. Here, you will find emission factors for driving as well as different types of public transport.

  3. For the chosen method of transport, find the column headed ‘kgCO2e’ as this will cover all greenhouse gases (which is how total emissions should be reported).

  4. Factors provided are per kilometre travelled, so take the total distance travelled and multiply it by the relevant emission factor. Note that the output from this calculation will be in kgCO2e, and normally carbon is reported as tonnes so you will need to divide the number you get by 1,000.

e.g. (100km travelled via bus x 0.10312)/1000 = total tonne of carbon for that journey

Using these conversion factors in combination with the distances returned by TravelTime, you can calculate an estimate of the emissions for different employees’ commutes to different offices.

How to calculate driving and public transport distances using the TravelTime API

Driving

When using the TravelTime API directly, simply include “distance” as a parameter under “properties” in the request. In the example below, we are calculating the driving distance for two employee commutes:

The response then includes the ‘true distance’ in metres (i.e. the distance driven along the road) for both employees’ commutes:

These calculations can also be performed using either the TravelTime plugin for QGIS, or TravelTime macros in Alteryx.

In QGIS, use the Time Filter Advanced tool, and select the “Properties / distance” tick box:

Time Filter Advanced tool

The Attribute Table of the created layer will then contain a prop_distance field:

attribute table

In Alteryx, use the Travel Time Matrix macro, and apply a filter for “Metric = distance”:

TravelTime Alteryx matrix macro

In the example below, we have then applied a Cross Tab tool to the resulting output. The table shows the distances between a number of employee addresses and two offices:

employee commute matrix

Public Transport

For public transport journeys, TravelTime does not return the exact route travelled by a train or bus (as this data is not always available) but it does return the lat-long coordinates of the stations or stops along the route.

Calculating the straight-line distance between these stops and adding them all together will give a good estimate of the total distance travelled.

The image below shows how this straight line between two train stations does not exactly follow the train line, but gives a very good approximation:

straight line distance between two stations

When using the TravelTime API directly, simply include “route” as a parameter under “properties” in the request. In the example below, we are calculating the public transport route for two employee commutes:

 

The response then includes a full breakdown of each route, including the lat-long coordinates of each leg of the journey. One leg of the journey for the first employee is shown below as an example:

commute journey lat-long coordinates

There are a number of ways to convert the lat-long coordinates of the public transport legs into a distance, but here is a useful online tool to help.

The benefits of travel time data for calculating CO2 emissions

At TravelTime, our primary focus will always be to help our customers analyse journey times to help them make better decisions when it comes to challenges like where best to locate an office.

Adding CO2 emissions data into this decision-making process helps our customers enhance their analysis further, and potentially use the site selection process to contribute towards wider business goals such as CSR initiatives.

While we don’t provide CO2 emissions data directly through our tools, we do provide distance data, which is almost always the foundation for calculating emissions. On top of this, TravelTime supports journey time analysis for any method of transport, including public transport, cycling, and walking — this data alone helps our clients promote greener transport modes for employee commutes.

If you’d like more information, please reach out to us at support@traveltime.com

And to begin your own CO2 emissions analysis, you can sign up for a free TravelTime API key.

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