Some companies have tried to put digital signage on the outside of taxis, this type of solution does not work, due to the taxi being in motion 90% of the time. Other limitations of this sort of transportation advertising is that the ads have to be small, one liners to capture the audiences attention.
Digital marketing on taxis, probably isn't for you if you are on a tight budget.
However, one of the best solutions we have seen for taxi advertising was inside a taxi in Dusseldorf, when we left the airport, the taxi had a small 9 inch screen that was also interactive.
Once you selected the language you wished the display to be in, you then had a choice of restaurants, nightclubs, hotels, theatres and cinemas to choose from.
So for example if you chose a restaurant from the display, a voucher code was displayed, so you mention this when you make a reservation and the code also corresponds to the taxi you saw the digital advert in, this way the advertising company can monitor the taxis routes that generate most business and can target that more effectively.
These digital out of home ads are highly efficient and perfect for tourists and locals alike, instantly capturing the attention of the passengers as soon as they enter the taxi, as soon as the passenger engages with the interactive display, it is beginning to log nationality and areas of interest, so specific demographics can be targeted even better.
Outdoor signage on taxis can be expensive, however a signage solution inside is cost effective and had a fast return on investment.
Digital Signage in Taxis - LCD Enclosures Global Explain