wiki
都営バス（とえいバス、英: Toei Bus）は、東京都が経営す
る公営バス。略称は、都バス（とバス）。

Since there's only one 都, this ends up 
referring to a specific company, 都営バス. We 
don't currently accept company names into 
jmdict, but I think we should, at least for 
companies dealing with public transport. The 
issue is currently being discussed (more or 
less) here;
https://github.com/JMdictProject/JMdictIssues/
issues/24

If we end up changing our policy, this entry 
can be revived then.

https://ejje.weblio.jp/content/都バス

obvious, but given that 市バス is an entry as well..? :P