CCRA mileage cost estimates include insurance, and are only for the first 3k or so miles per year, then there is a reduced rate. I have found it pretty accurate. It is based on a 3-4 year old sedan (such as a ford taurus or honda accord), with depreciation, maintenance, fuel and insurance, replaced every 6 years or so.

The rates are: The automobile allowance rates for 2016 and 2017 are:

54¢ per kilometre for the first 5,000 kilometres driven; and

48¢ per kilometre driven after that.

Ignoring the km versus miles and US versus CDN, I think you can take the ratio of 48:54 and apply it to you.

So, if you are at $0.50 per mile for the first 3000 miles, then 44.5 cents per mile thereafter..

Assuming 48 miles per day x 5 days per week x 46 weeks per year (net of vacation and federal holidays) = 11,040 miles per year.

3000 miles x 50 cents = $1500

8040 miles x 44 cents = $3537

Total = $5037 per year. Plus parking (if any) minus bike costs (if any).

You need to decide how much less a prius costs to operate, than a 4 year old gas sedan, and adjust the final total.