The table illustrates how citizens in Houston, Texas commuted to work, and the bar chart delineates the travel problem they experience.
Looking from an overall perspective, the majority of people use cars, which is also the factor causing the most pollution. While the proportion of commuters riding bicycles or walking is the lowest, it is environmentally friendly. However, most young people choose to walk or cycle, whilst the average age of residents commuting by bus or train is the highest.
Looking at the table more closely, it can be seen that 48 percent of citizens commute to work by personal cars, and 11 percent of citizens go to work by sharing the cars, making the car the most popular means of conveyance in Houston. Although the proportion of people using the train or bus is the second highest at 37 percent, it is a transportation choice with the highest average age of passengers at 47 years old. This is 4-year older than the average of residents using private cars and 3-year older than people using the sharing cars. Nevertheless, just 4 percent of people commuting to work by bicycle or walk, but most people who choose this are young people, at 39 years old.
According to the bar chart, it is apparent that around 0.32 kilograms of CO2 per person per kilometer is the figure for commuters who travel alone by car, it is the witness that this is the most polluting way. While citizens traveling to work by the sharing car produce approximately 0.08 kilograms of CO2 per person per kilometer, those using public transport emit about 0.01 kilograms of CO2 per person per kilometer. Only people commuting by bicycle or walking do not contribute to the environmental pollution when absolutely no carbon dioxide is released.