 unsigned long current_time = 0;
 unsigned long last_time = 0;
 double delta_time = 0;
-// Distance in degrees
+// Distance in mi
 double current_dist = 0;
 double last_dist = 0;
 double delta_dist = 0;
+// Bearing in degrees
+double current_bearing = 0;
 // ETA in milliseconds. If negative, we're traveling away from current_dest
 double eta_time = 0;
 

  double a = pow(sin(dlat/2), 2) + cos(from.lat) * cos(to.lat) * pow(sin(dlng/2), 2);
  double c = 2 * atan2(sqrt(a), sqrt(1-a));
  return EARTH_RADIUS * c;
}

// Stores a value for the sliding window average

  current_dist = distance(current_loc, current_dest);
  delta_dist = current_dist - last_dist;

  current_bearing = bearing(current_loc, current_dest);

  eta_time = -delta_time * current_dist / delta_dist;
  put_avg(eta_time / 1000);
}
