The feasibility study is part of work it is doing for the Department for Transport and the National Business Travel Network.
The consultancy said that over the past ten years, the private sector's uptake of travel plans has been poor except where required by planning permission or in response to a specific problem such as car parking.
While evidence for travel plans' impact on reducing car use is becoming stronger, there is a lack of detailed understanding of their financial benefits.
Colin Buchanan's initial findings show that direct benefits such as savings on parking, reduction of car mileage claims and fleet management costs can be measured accurately.
But it also discovered that there are gaps in data on indirect benefits including increased productivity, reduced absenteeism, higher customer turnover and improved staff retention.
Senior transport planner Chris Hanley said: "Greater understanding is needed in the private sector of cost-saving measures that can be included in travel plans."
Colin Buchanan is due to consider key case studies in more detail and use the results to assess whether a financial calculator can be developed to estimate anticipated savings.
The consultancy will also carry out an economic appraisal of the cost-benefit ratio of travel plans compared with other more traditional transport interventions.