Significant alleviation of the road-trafic noise nuisance requires a range of measures, including technical improvements in vehicles and regulations to enforce their use: restrictions on trafic in certain areas (e.g. hospital zones) and at certain hours of the day, improvements in housing design (e.g. double or triple glazing), and greater attention to noise radiation in highway design (e.g. the use of vegetation buffer zones). The problem of airport noise is function of the location and size of the a facility but is an increasing hazard around many cities in the developed world. Residential areas under the flight path of major international airports such as London Heathrow or New York's JFK have to endure fights every few minutes at peak periods. Resolution of this problem requires a combination of technical improvements to jet engines to reduce noise at source, insulation of dwelling units near flight paths, land-use controls informed by accurate delimitation of noise exposure zones, and geographical research to determine the optimal aircraft flight paths over any urban area