A vehicle comprising: tyres; a brake system ; and a brake duct system comprising: a first outlet configured to be disposable adjacent to the brake system ; a second outlet configured to be disposable adjacent to the brake system; a first duct arranged to convey air to the first outlet; and a second duct arranged to convey air to the second outlet; the brake duct system further comprising a vortex tube having: an inlet arranged to collect air at a first temperature, and at a pressure substantially above atmospheric pressure; a high temperature outlet configured to supply a first stream of air at a second temperature substantially above the first temperature to the first duct to convey the first stream of air to the first outlet; and a low temperature outlet configured to supply a second stream of air at a third temperature substantially below the first temperature to the second duct to convey the second stream of air to the second outlet; characterised in that the first outlet is arranged to heat up the brake system and/or heat up the tyres . tyres; a brake system ; and a brake duct system comprising: a first outlet configured to be disposable adjacent to the brake system ; a second outlet configured to be disposable adjacent to the brake system; a first duct arranged to convey air to the first outlet; and a second duct arranged to convey air to the second outlet; the brake duct system further comprising a vortex tube having: an inlet arranged to collect air at a first temperature, and at a pressure substantially above atmospheric pressure; a high temperature outlet configured to supply a first stream of air at a second temperature substantially above the first temperature to the first duct to convey the first stream of air to the first outlet; and a low temperature outlet configured to supply a second stream of air at a third temperature substantially below the first temperature to the second duct to convey the second stream of air to the second outlet; characterised in that the first outlet is arranged to heat up the brake system and/or heat up the tyres . a first outlet configured to be disposable adjacent to the brake system ; a second outlet configured to be disposable adjacent to the brake system; a first duct arranged to convey air to the first outlet; and a second duct arranged to convey air to the second outlet; the brake duct system further comprising a vortex tube having: an inlet arranged to collect air at a first temperature, and at a pressure substantially above atmospheric pressure; a high temperature outlet configured to supply a first stream of air at a second temperature substantially above the first temperature to the first duct to convey the first stream of air to the first outlet; and a low temperature outlet configured to supply a second stream of air at a third temperature substantially below the first temperature to the second duct to convey the second stream of air to the second outlet; an inlet arranged to collect air at a first temperature, and at a pressure substantially above atmospheric pressure; a high temperature outlet configured to supply a first stream of air at a second temperature substantially above the first temperature to the first duct to convey the first stream of air to the first outlet; and a low temperature outlet configured to supply a second stream of air at a third temperature substantially below the first temperature to the second duct to convey the second stream of air to the second outlet; characterised in that the first outlet is arranged to heat up the brake system and/or heat up the tyres . <EOS>