Belt-driven bicycle with a compact design that, like STRiDA, featured a belt drive. Other folding-bike manufacturers that have implemented a belt drive include U.S. company Bike Friday and Netherlands-based Bernds. In 2007, Gates Corporation developed a high-modulus synchronous belt and sprocket system called the Carbon Drive System. The belt’s pitch allowed for lower tension requirements to help prevent skipping. Lightweight, patent-pending sprockets have mud ports, openings under each tooth, which work to slough off debris. In 2009, an increasing number of bicycle companies, including Trek and "f"8 Cycles, offered belt-driven bicycles. While builders initially focused on single-speeds and internal hubs, in early
Bicycle helmet laws by country helmet use. Australia was the first country to enact mandatory bicycle helmet use for all cyclists. Mexico City has had mandatory cycle helmet laws repealed, and in Italy the Federazione Italiana Amici della Bicicletta managed to block a proposed helmet law. While bicycle helmets are not required to be worn by law in the United Kingdom the British Medical Association advocates the compulsory use of helmets. Cycling UK, the largest cycling advocacy organisation in the UK, consider helmet wearing as personal choice rather than being mandated by legislation. In 2002 an attempt was made to introduce bicycle helmet legislation in