TriMet SIMS

SIMS overview

TriMet's Service Incident Messaging System (SIMS) is a common interface for TriMet dispatchers, road operations, and public information officers to construct and send messages describing service interruptions such as detours, stop closures and emergencies.

Currently SIMS is used to create service alert messages and emergency box alerts for the trimet.org home page, alerts page, TransitTracker and web Trip Planners. SIMS also allows road operations to create block-specific reroute sheets, so that Station Agents don't have to copy reroute sheets for each affected block. It is also used to create and edit standard snow route messages to be imported into the BDS "special" reroutes menu.

See instructions.

Unfinished development

SIMS was originally created to allow dispatchers to schedule or send a batch of pre-defined detour messages associated with a "scenario" such as a bridge closure, a parade, or a "typical" snowstorm such as snow in the west hills above 500 feet, an ice storm in the east county, or a city-wide storm. This feature is enabled in SIMS but was never integrated with BDS.

Initial design

SIMS has pages for defining standard detours (reroutes) and for associating them with regular routes and scenarios. It also has pages for scheduling or sending reroute messages.

"Alerts" are reroutes that have been or will be put into effect within specific time frames. The time frames may be limited to specific service types (such as weekdays or weekends) or within specific hours of the day, or "all hours" or "all days." They may define a specific end date and time, or "until end of service" or "until further notice." An alert may be associated with any number of time frames since it's possible to be detoured by a construction project that closes a street or bridge nights and weekends only.

A standard reroute in SIMS consists of several messages:

1. A short radio message (up to 200 characters) for broadcasting to the affected route or routes.
2. One or two supplemental radio messages describing the reroute in detail.
3. A cancel message.
4. A detailed description to be printed on a reroute sheet (not yet implemented).
5. A public description of the detour to be posted on the TriMet web site. The public description is also shown as a footnote on any trip plans that use an affected route.
6. A pre-recorded announcement for the public telephone system (not yet implemented). If not defined, the phone system records a text-to-speech message from the public description.

A standard scenario is simply a list of reroutes. A reroute may belong to any number of scenarios. The scenarios are organized by context: Snow/Ice, Bridge Closure, Construction, Event, Flood, MAX (light rail) Bus Bridge, or Traffic, plus a "Miscellaneous" context as well as "Draft", "Test" and "Old".

The process for scheduling a scenario is now enabled in SIMS, but sending messages to BDS is disabled until BDS can be configured to receive them.

When enabled, a dispatcher will select a scenario to see a page that shows a list of reroutes with controls for defining a time frame. The time frame defaults to "now until end of service", but may be set for a specific time frame. The dispatcher may queue all reroutes in the list, or may un-check any reroutes to exclude them.

Selected reroutes are initially queued as "Draft" alerts. Queued alerts may be sent immediately as-is, or may be edited without affecting the standard messages.

Any reroutes within a scenario that are already scheduled or in effect are shown in a separate list. The dispatcher may re-schedule or cancel any or all of these, or may schedule or send any or all of the remaining reroutes defined in the scenario. This allows sending a limited scenario followed by a broader scenario without sending duplicate messages.

The system currently checks only for duplicate reroutes. It should also check for contradictory messages, such as service on a route being detoured or canceled, but that is not yet enabled.

When reroutes are canceled, SIMS sets the time frames for the public alerts to end now. If a reroute is canceled after sending a message to BDS, then SIMS will a send predefined cancel message. Otherwise, it removes the scheduled alert from the database.

It is now possible to define reroutes and scenarios within SIMS and to schedule alerts to be displayed on the public web server, trip planner and "Transit Tracker" systems. It is not yet possible to send radio messages from SIMS through the Bus Dispatch System (BDS). In the interim, we are exporting new reroutes from SIMS into a table in BDS that allows dispatchers to select and send individual reroutes. During a recent ice storm, that system proved inadequate as it took so long to select each reroute and send it to the appropriate routes that the information being transmitted and published was incomplete, inaccurate or contradictory. SIMS was intended to address that problem.

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