For the most part, road travel is not strongly recommended for Cascais.  This has little or nothing to do with the conditions of road travel in the city and everything to do with the fact that alternatives to road travel are readily available.  For the most part, visitors can get around Cascais via walking or bicycling and they can supplement such travel options with local public transportation.  See http://www.tripadvisor.com/Travel-g18... and http://www.tripadvisor.com/Travel-g18... for more information.

However, many people do end up renting cars in the area, and there is no particular reason not to do so.  Most people who do so have arrived in the area by flying in to the Lisbon airport (see http://www.tripadvisor.com/Travel-g18... for additional information) and they choose to rent cars while at the airport in order to proceed on to Cascais.  Major car rental companies represented at the airport include Avis ( www.avis.com) and Budget ( www.budget.com).

Taxi hire is possible in Cascais, but it is not a frequently used option by most people, again because of the prevalence of other transportation options.  Taxi hire is definitely not used for people coming from the Lisbon airport, as it is far less expensive to take the train or bus from the airport to Cascais.  Within Cascais, taxis can be called for pick up.  More information is available at http://www.infotaxi.org/city-907.htm.