MUMBAI: This is one traffic stopping study all agencies would die to get their hands on.

Nielsen Media Research, the giant of broadcast ratings, will begin testing an outdoor ratings system in Johannesburg, South Africa, while another giant, Arbitron, will conduct a similar test in Atlanta later this year. The outdoor advertising industry, supported thus far by counts of cars passing particular billboards and other displays, provided by the Traffic Audit Bureau. Now, the Outdoor Advertising Association has pledged a whopping $ 3,15,000 for the two studies to enable the compiling of demographic data, a first for the industry. Outdoor receives about four per cent of US advertisers' budgets, compared to eight per cent in the rest of the world, says Arbitron.

Arbitron plans to release results from its Atlanta test in next year's second quarter. Its system uses a combination of travel diaries kept by 1,000 consumers and a portable global positioning system carried by a subsample of 50 people to track exposure to outdoor messages both in-car and out-of-home. The big sample size ruled out using all electronic methods of compiling the data needed, hence the use of diaries. The Arbitron system can be used affordably in top 25 markets.

With additional backing from outdoor companies including Clear Channel Outdoor and JC Decaux, Nielsen will test an in-car GPS system with 100 consumers in Johannesburg. If the test is successful, Nielsen plans to test a portable GPS device next year in a US market. Neither system is however likely to replace the TAB's traffic counts. "Both initiatives can enrich information about outdoor by providing demographics," says TAB president Joe Philport. "We'll work with both."