Tomtom used to have an individual "# of map corrections in use" report, but ever since the HOME bug that tells everyone to buy a subscription, that report has been hidden.
Tomtom claims the following IQroutes data in
this press release:
- Data derived from more than 600 billion speed measurements shared by consumers in 26 countries over the past two years;
- Coverage for 24 European countries, encompassing 15.5 million kilometers and complete coverage of the navigable road network;
- Coverage in North America for Canada and the United States, encompassing 19.5 million kilometers and approximately 90 percent of the navigable road network; and
- 77 percent of frequently traveled roadways with actual average speeds for every five minutes of the day on any day of the week.
My guess is that 10-20% of Tomtom users plug in at some point, either to buy new maps or get quickGPSfix data. Mapshare alone gives users a good reason to plug in.
Also, Tomtom didn't license QuickFixII from sirfstar (as Garmin did on their higher-end models), which was a non-plugin approach to QuickFixI (called QuickGPSfix in tomtom speak). You could consider that a conscientious cost-saving / quality decision since QuickFixI offers faster satellite acquisition than QuickFixII, or a more sinister attempt to force people to plug in their tomtoms to supply data.
