Informational article

Sigalert: How to Get Traffic Alerts for Southern California Roads

Sigalert is a free, real-time traffic alert service operated by the California Department of Transportation (Caltrans) that provides up-to-date incident and road condition data for all Southern California state-maintained freeways and highways, and drivers can access these alerts via the official Sigalert website, dedicated mobile app, or third-party navigation platforms that integrate Caltrans traffic data, with options to customize notifications for specific commutes and routes. ## Sigalert Coverage Area for Southern California Sigalert monitors all state-maintained freeways, high-occupancy vehicle (HOV) lanes, and major highway corridors across Los Angeles, Orange, Riverside, San Bernardino, Ventura, and San Diego counties. The service updates incident data every 2 minutes, tracking accidents, disabled vehicles, road construction, lane closures, and speed trap locations to give drivers accurate, timely information about conditions that impact travel time. It does not cover local city streets or unmaintained rural roads, so drivers traveling on those routes should reference local county or city public works alerts for updates. ## How to Access Sigalert Traffic Alerts The official Sigalert website (sigalert.org) hosts a free, public-facing live map of all current incidents across the region. Drivers can enter specific freeway numbers and mile markers to check conditions for a particular segment, or input start and end addresses to view alerts for a full planned route. Free email and text alert subscriptions are available for custom routes, with standard carrier messaging fees applying to text alerts only. Caltrans offers a free official Sigalert app for iOS and Android devices, which sends push notifications for incidents on saved routes, includes offline map access for areas with limited cell service, and lets users adjust alert sensitivity to avoid unnecessary notifications for minor, low-impact incidents. Most major consumer navigation apps, including Google Maps, Waze, and Apple Maps, pull Sigalert and Caltrans traffic data directly, so drivers can receive real-time traffic alerts embedded in their regular turn-by-turn navigation without accessing a separate platform. ## Customizing Alerts for Your Regular Commute For the official Sigalert platform, users can save up to 10 custom routes by entering start and end points or specific freeway segments. Alert settings can be adjusted to only trigger for incidents that add a minimum travel time delay (such as 10 minutes or more) or for severe events like full highway closures or injury-involved accidents. For navigation app users, enable traffic alert toggles in the app’s settings to prioritize Sigalert-sourced data for your saved home and work routes, and opt in to rerouting suggestions when incidents impact your planned path.