The UK Department for Transport’s research called: "Making Travel Plans Work, Lessons from UK Case Studies" found that really basic Travel Plans can reduce driver only car journeys to work by 3% to 5% and Travel Plans with large public transport fare discounts and car parking restrictions or charges were achieving 15-30% reductions, some even more.

These figures are based on the Department’s review of 20 organisations that had successfully brought about changes in the travel patterns of their staff.

PAN57 said it was not always the case that the most resource intensive Travel Plans had the most effect in reducing the percentage of people driving. Research had demonstrated that Travel Plans:

• Containing only marketing and promotion were unlikely to achieve any modal shift.

• With car sharing and cycle measures might achieve 3-6% reduction in drive alone commuting.

• With the above measures plus large (30%+) discounts on public transport plus works buses, might achieve around 8-13% reduction in drive alone commuting.

• Containing a combination of all the above measures plus disincentives to car use might achieve a larger (15-20% +) reduction in drive alone commuting.

PAN57 included the following table. The score in the right hand column indicates the level of effectiveness of each measure in reducing single occupancy car usage.

Depending on the combination of measures used, one could expect to see a reduction in single occupancy car usage as follows:

• 8 points or less: a 3 to 5% reduction.

• 8 to 16 points: 5 to 10% reduction.

• 16+, which must include parking restrictions: 10 to 15% reduction.

For example, a Travel Plan containing a new computer based car sharing scheme (2 points), a redirected bus service (2 points), easily accessible public transport information (1 point), new cycle facilities (say 4 points) and promotional activities (1 point) accrues a total of 10 points altogether. This comes in the range 8 to 16 points which implies that single occupancy car trips could be expected to reduce between 5% and 10%.