{"id":3266,"date":"2013-09-07T17:52:11","date_gmt":"2013-09-07T21:52:11","guid":{"rendered":"http:\/\/www.alexblock.net\/?p=3266"},"modified":"2013-09-07T17:52:11","modified_gmt":"2013-09-07T21:52:11","slug":"speed-urban-transportation-and-geometry-heuristics","status":"publish","type":"post","link":"https:\/\/www.alexblock.net\/blog\/2013\/09\/07\/speed-urban-transportation-and-geometry-heuristics\/","title":{"rendered":"Speed, urban transportation and geometry heuristics"},"content":{"rendered":"

Following up on this previous post, noting that “transport is mostly a real estate problem”<\/a> – a few quick heuristics on cities, speed, and space:<\/p>\n

\"Comparison<\/a>

Comparison of population\/employee density and street area per person. Image from NYU Urbanization Project.<\/p><\/div>\n

Regarding speed:\u00a0<\/strong><\/p>\n

Speed requires space; faster travel occupies a larger area than slower travel.<\/p>\n

Speed alters our perception of space<\/a>. Faster travel makes large things seem smaller<\/a>\u00a0(hat tip to this post from GGW<\/a> for the links). The properties of the space affect how we use it and what we percieve it to be; wider roadways within streets get used for faster travel<\/a>.<\/p>\n

Regardless of speed, cars require large spaces relative to their capacity. Even when parked (v = 0), cars require lots of space. By extension, building cities around\u00a0requires a completely different spatial footprint<\/a>.<\/p>\n

Regarding space:\u00a0<\/strong><\/p>\n

There is a strong tendency for cities to\u00a0devote about 25% of their land to streets<\/a>. Street networks are for mobility, but also for access to land. Devoting too much land to streets is wasteful; too little makes it difficult to unlock the value of the land within a city.<\/p>\n

Intersection density correlates with walkability<\/a>\u00a0and connectivity; wider instersection spacing correlates with the higher speed travel of cars<\/a>.<\/p>\n

Consider the relationship between the density of the network (intersection density), the tendency to use ~25% of land for streets (regardless of the density of the place<\/a>), and street width on the kind of transportation.<\/p>\n

Simply requiring some minimum intersection density for new developments via a code will still be subject to ‘gaming’ and open to unintended consequences<\/a>.<\/p>\n

Street networks are sticky and tend not to change once established<\/a>; the cities that grow around them are path-dependent<\/a>. However, transport networks can be layered – subways travel fast, require space and grade-separation, but deliver passengers to the street grid as pedestrians; just as freeways are layered above\/below streets and deliver high volumes of cars to local streets.<\/p>\n

While the physical space allocated to streets tends not to change, the use of that space can change a great deal<\/a> over time.<\/p>\n","protected":false},"excerpt":{"rendered":"

Following up on this previous post, noting that “transport is mostly a real estate problem” – a few quick heuristics on cities, speed, and space: Regarding speed:\u00a0 Speed requires space; faster travel occupies a larger area than slower travel. Speed alters our perception of space. Faster travel makes large things seem smaller\u00a0(hat tip to this […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[1],"tags":[138,221,210,230,174,474,477],"class_list":["post-3266","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-3ds","tag-intersection-density","tag-networks","tag-speed","tag-street-space","tag-transit","tag-unintended-consequences"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pHcGQ-QG","jetpack_sharing_enabled":true,"jetpack-related-posts":[],"_links":{"self":[{"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/posts\/3266","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/comments?post=3266"}],"version-history":[{"count":9,"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/posts\/3266\/revisions"}],"predecessor-version":[{"id":3275,"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/posts\/3266\/revisions\/3275"}],"wp:attachment":[{"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/media?parent=3266"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/categories?post=3266"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.alexblock.net\/blog\/wp-json\/wp\/v2\/tags?post=3266"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}