Price my journey

Price my journey is an idea I've come up with for a mobile app and website and a browser addon. The app adds new functionality to google maps helping you work out how much it’ll cost you to drive places and how much co2 will be emitted during the journey. "Price My Journey" the name of the app can help you make informed decisions everyday so you can minimise your impact on the environment, by making your aware of how much you could save by driving a smaller car, living closer to work or generally driving less. Biking or walking more where possible. You your family and friends can save money, get fit and do good by the environment by using Price My Journey.

Price My Journey lets you choose your car from it’s database and helps you work out exactly how much it’ll cost you to get from place to place as well as making you more aware of your environment without you having to do any calculating. Price My Journey shows you current local fuel prices it can even help you divide up your trip cost between your friends. 

“grease monkey” lets you interact with content on pages and add buttons that make calculations with data and pull information from other websites.
This is how extensions are made. Extensions are just javascript and css. If you used css alone and no javascript you could port it to userChrome.css or userContent.css. I don't know what the chrome and android equivalents are. Although css is supposed to be uniform it isn't. Code that works in Firefox may not work in chrome. Then there are different versions of css - I have things that work in Fx8 but not in Fx3.
To have a look at what grease monkey can do check out “userscripts.org”
userstyles.org  it a site that hosts lots of different ccs styles that interact and change the websites you view
An international tool.
http://en.wikipedia.org/wiki/Greasemonkey 

Fuel price data could be scraped from a website like pricewatch Another option would be to partner project up with a retail fuel company and show their regional price and logo. This option is much more economical and could help fund the project. The information on the pricewatch website is very secure they may charge for access to their data can't simply scrap the data from this site which is a shame.

I've got all the information to build a very full database of cars which includes the information above if you are interested the link for these files is at the end of the article.

Vehicle id
Vehicle id Number 0000000
Year
Make
Model
Gears
Style
Doors
City Consumption (Litres/100km)
Highway Consumption (Litres/100km)
CO2 Emissions (CO2 grams/km) 
To view files collected for this project click here

CO2 emissions conversion factors used are as follows:

• Premium petrol – multiply the L/100km by 23.414 to give CO2 grams/km
• Regular petrol – multiply the L/100km by 22.847 to give CO2 grams/km
• Petrol (average) – multiply the L/100km by 22.961 to give CO2 grams/km
• Diesel – multiply the L/100km by 26.050 to give CO2 grams/km

http://www.gasbuddy.com/Trip_Calculator.aspx is a similar website but it isn’t quiet as good as an app that links into google maps website, as well as better branding and layout as-well