The Costs of Your Commute: Your Money, Your Time, and the Earth

This page authored by Charles Buehrle, Harrisburg Area Community College.
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In this activity we want to compare not only the cost of one day of commuting, but also the CO2 output. We also want to compute the total travel time. Students collect data on their commute (number of miles, vehicle's miles per gallon, travel time). Then students investigate an alternative option for their commute that could be more environmentally friendly (mass transit, carpooling, biking, etc.). For mass transit options the student would collect data on fare costs, estimated travel time and type of vehicle (bus, train, diesel, hybrid, etc.).

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Learning Goals

This activity...

Can serve as an introduction to thinking about personal impact on the environment while still appealing to personal costs.

Engages students in civil discourse/ communications that lead to more effective decisions.

Encourages self-reflection and personal development of their voice for solving societal challenges

Helps students create a comparative metric needed for dimensional analysis (unit conversions).

This activity also requires minor research skills and the ability to discern between reasonable data (useful rates, averages, etc.).

Context for Use

The activity requires access to the Internet to input student data on their vehicle and the alternative commute option. This could be done in a computer lab or with laptops/tablets in a traditional classroom. The time expectation would be a single (50 minute) class period, but the possibility of expansion into longer time periods is easy to accomplish.

Description and Teaching Materials

The activity could be introduced by asking the students "What is the impact of your commute?"

Depending on the students' responses, a follow up question would be "How can we measure the impact?" With some direction, students would likely come to the answers such as:
- cost (in dollars) of operating their vehicle;
- kilograms of CO2 (or equivalents) released by the vehicle;
- travel time incurred.

These measures of impact lead to the students researching specific information on their vehicle's fuel efficiency, average price of fuel, CO2 emissions from burning a gallon of fuel, and estimated travel time using an online mapping service.

Students would then calculate a single day's costs for their commute in dollars, kilograms of CO2, and hours.

Now the students should be posed to address a question like "What would be an alternative, more environmentally conscious, way of commuting?"

Based on students' responses they could each investigate their personal alternative, like mass transit, or they could be broken into groups, where each group investigates a specific alternative.

For mass transit, the students might be expected to look up available routes, fares, estimated travel time, traveled distance, fuel type used, and the CO2 output of that type of vehicle and fuel.

Then they would compute the costs of the alternative in dollars, kilograms of CO2, and hours.

With other alternatives, similar quantities could be computed.

The students would then be asked to compare. To aid in the comparison, suggest that students to look at ratios of the data like dollars per hour and kilograms of CO2 per hour.

Finally the students would be asked "Would using an alternative method of commuting, even once a week, make an impact?" Follow-ups would be "Are there other ways we could save money, carbon, or time?"

Teaching Notes and Tips

Keeping students on task would be the biggest concern. Emphasize that they are really using math to help themselves and possibly the planet.


At the end of the period, time permitting, each student or groups could present their findings to the entire class and discussion could commence afterwards.

References and Resources - This webpage has useful data and formulas for computing costs of commuting. - This site has information on bus fuel efficiency. - This site also bus fuel efficiency information. - This site is a resource for finding vehicle MPG ratings. - This site has information on average cost per gallon of gasoline. - This document provides data on the amount of CO2 released from burning a gallon of gasoline. - This site has information on personal mile per gallon for commuter travel.