Transit systems also have an effect on derived businesses: commercial websites have been founded, such as Hopstop.com, that give directions through mass transit systems; in some cities, such as London, products themed on the local transport system are a popular tourist souvenir. Research in the Washington, DC area shows that public transport does a better job of providing high-skill residents with access to high-skill jobs than it does mid-skill residents to mid-skill jobs and low-skill residents to low-skill jobs. Because night trains or coaches can be cheaper than motels, homeless persons sometimes use these as overnight shelters, as with the famous Line 22 ("Hotel 22") in Silicon Valley.