How fast do cars actually go?

Summary

I calculated the average speed that people achieve in cars, considering their actual average speed on the road, and the time they spend earning the money to maintain their cars. I found that, for an above-average income ($60000/year), a person driving 10000 km/year achieves an average speed of only 22.9 km/h. If you earn less than this, you must spend more time earning money to pay for your car, and your average speed is lower still.

How fast to cars go?

What I want to do in this article, is work out how fast people actually travel when they're driving cars. I want to consider actual average road speeds, and also consider the time they spend earning the money to pay for their car and its maintenance.

Traffic Speeds

Average speed of urban traffic in Australia, by time. Source: https://www.bitre.gov.au/publications/2007/files/wp_071.pdf, page 104

This paper, has the 2005 statistics for vehicle speeds in Australia. From it I got this figure, showing that the average speed of cars in urban areas during the day time is about 42 km/h. Of course, congestion has got worse since then, and I would expect average speeds today to be lower, but I couldn't find those statistics.

Combine with time spent earning the money to pay for the car

Across Australia, once on the road, your average speed in the city is about 42 km/h (more like 37 km/h during peak periods). But what about the time you spend earning money to pay for your car? To work this out, I extended this spreadsheet (previously introduced in this article). It now also calculates the average speed of a motorist, based on the 42 km/h on-road speed and the time they spend earning money to pay for the car.

The average speed they attain depends on how much they drive -- as someone drives more, the marginal (time) cost of each extra kilometer decreases so their average speed increases. Here are some examples:

• For a person on an above-average wage, driving 10000 km per year, they average just below 23 km/h
• For a person on the same wage, driving 5000 km/year, they average just below 18 km/h
• They won't reach an average of 30 km/h until they are driving 80000 km/year
• For a person on $40000/year driving 10000 km/year, they average 18.5 km/h

Conclusion

1. When you consider the time spent to pay for a car's maintenance, and the actual speed you achieve on the road, cars are not actually a quick way to get around. 
2. The cost, to the taxpayer, of car infrastructure is huge -- I question whether it is good value for money.

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This article was written by Angus Wallace and first appeared at
guesstimatedapproximations.blogspot.com.au

What does it cost to own a car?

There have been a few good articles recently about the social cost of cars. Here is a good one -- it nicely summaries what many people are unaware of: vehicle registration does not pay for car infrastructure. Cars require a taxpayer subsidy.

People who ride bikes subsidise people who drive cars.

Here, I want to explore something different.

1. What does car ownership cost its owner?
2. How much time must the average car owner work to pay for their car?

These questions aren't often asked, so I ran a few numbers in a simple spreadsheet, which can be viewed here.

The cost of car ownership:

A private citizen on a slightly above-average income will spend 2.75 hours per week working to pay for their car. This includes a very small mileage (less than 40 kms/week). As the weekly distance driven increases, so too does the cost, though the cost per distance decreases.

A private citizen on a slightly above-average income will spend 2.75 hours per week working to pay for their car.

I ran the "model" with a heap of [distance travelled] options to explore how much work was required. I estimated several things:

1. work hours per week
2. Cost in Australian dollars per kilometer driven
3. time spent working, per distance. This is measured in hours per 100km per week. This is the time that is worked by the car owner, each week, for each 100/kms they drive.

What I found really interesting is that it is really expensive.

For a person who drives 10000 km per year (just under 200 km per week) they must work nearly 4 hours per week, which equates to more than 2 hours work per 100km per week, for a total cost of $0.44/km driven. Suddenly public transport is looking very cheap indeed. Remember, this is the private cost borne by the car owner, and does not include all of the public costs borne by the Australian taxpayer.

A total cost of $0.44/km driven -- a limo is cheaper!

As you drive less, owning a car makes even less sense. For someone who drives 3000 km per year, the cost is more than $1 per kilometer. You could catch a limo cheaper than that!

Conclusion

Owning a private car does not make economic sense, even with the strong public subsidies that currently exist. Of course, the bottom line is not the only consideration, so I understand that people will want to keep a car, just for security and convenience. However, if you are a household with more than one car, I would strongly encourage you to consider getting rid of one car and exploring other forms of transport. Your wallet, and your country will thank you!

This article was written by Angus Wallace and first appeared at

guesstimatedapproximations.blogspot.com.au

Bike to work day

Cycling organisations like bikeSA often promote initiatives like bike to work day. I think this is a good way of encouraging people to view cycling as a means of transport instead of just something fun to do.

I think that bikeSA should also consider running a drive to work day -- where everyone who would normally cycle, drives instead (with the consequent traffic chaos). Perhaps this would help motorists to appreciate the service that cyclists are providing and discredit the idea that cyclists are freeloading.


This post was written by Angus Wallace, and first appeared on guesstimatedapproximations.blogspot.com