Drink-driving is prohibited in Japan, so you cannot drive after drinking. But if you leave your car and go home by taxi, you cannot drive to your office the next day.
Cars used for daikō are not equipped with meters like taxis, so you have to bargain with the driver over the fare. In my experience, the fare is the same or less as that of taxis in Kochi City.
Some daikō businesses offer special discount services; there is a business which provides 10-15%discount for a yellow plate car and 10% off for a woman, and another business offers you up to ¥1,000 off if your license plate number corresponds with the winning number which the business sets every month.
Unlike taxis, cars used for daikō have a sign “代行” in Chinese characters equipped on the car roof and almost all of the mare yellow plate cars (see the picture). Around restaurant districts at night there are plenty of daikō cars waiting for customers so you may have trouble choosing one of them. In such a case, it would be better for you to ask someone such as a coworker which company is good beforehand.
This service is indispensable in Kochi where public transportation services including trains and buses are not enough. The number of daikō businesses in Kochi is extremely high per capita in comparison with big cities such as Tokyo. This fact tells us what an important role the daikō service plays in Kochi.
Taken from vol.39 PDF