(Part of Open Source Transport Informatics tools listing, for the OSSTIP project, especially OSSTIP/WP2- Transit Informatics tools review.)
Mapumental (http://web.archive.org/web/20200103062826/https://mapumental.com/) was developed by the UK NGO MySociety and launched in 2009, with support from Channel 4 who helped purchase access to needed data, and Stamen Design. It was able to show isochronal time maps for journeys to UK Destinations.
Originally the project's code was published as Open Source and queries could be run over the web on an invited beta basis. However, later the project was made proprietary in an effort to convert it to an income-generating source for MySociety's other activities.