Lowering the posted speed limit over a large area can be more effective than a limit on a single street.
Toronto is split into four Community Councils, made up of the Councillors from the Wards within that district. Each has its own branch of Transportation Services, and many decisions about local and collector roads are made by Community Council.
In May of 2015, the Toronto and East York Community Council voted to lower the default speed limit from 40km/hr to 30km/hr on all local roads and some collector roads. This was done in response to demands for safer streets from local communities.
A similar reduction in your Community Council area could have a major impact on a large part of the city. Such an initiative would need significant community support including from other school and community groups from each of the wards in your district, as well as studies by City staff.