Motorcycle taxis on the sidewalk between Sukhumvit Soi 18 and Soi 24 are a serious nuisance and hazard to pedestrians. They also serve no useful purpose. They are used for short distances that the passengers, often teenage students, could walk in a few minutes. I saw one motorcycle post rider on the sidewalk snatch purses late at night. The Bangkok police need to be instructed to stop the dangerous and idiotic practice of allowing motorcycles to harass and endanger pedestrians on sidewalks.