diff --git a/src/tpm.c b/src/tpm.c
index a782ede..b5494a3 100644
--- a/src/tpm.c
+++ b/src/tpm.c
@@ -33,9 +33,13 @@ int tpm_is_inside_zone(tolling_info_t* ti) {
     itss_space_unlock();
 
     if (itss_is_inside_polygon(point, ti->zone.polygon, ti->zone.polygon_len)) {
-        return 1;
+        uint16_t da = abs((int16_t)heading - (int16_t)ti->asn->angle);
+        if (da <= 900 || da >= 2700) {
+            return 1;
+        }
     }
 
+
     return 0;
 }