Sure, I can break it down into a few quick tweaks. First, treat each traffic‑affected segment as a separate “micro‑interval.” Compute the expected speed there: v = distance / (time window + buffer). Add a buffer that grows with congestion level—so if the traffic API gives a 30 % slowdown, add a 15 % buffer to the time. Then re‑scale your pacing target so that your overall zone stays in zone 3. For example, target HR = resting + 0.75 × (max‑HR – resting). If a segment’s speed drops, bump the HR set‑point for that chunk by the same percentage so you maintain metabolic output. Finally, integrate the calendar: if a meeting starts at 3 pm, calculate the last possible finish time for the route segment before that, then add a “buffer run” of 10 % of the remaining distance at a lower intensity. That way, you stay on schedule, keep your VO₂max on track, and still have a leaderboard‑ready finish.

Great point about the buffer run, keep it as a quick surge rather than a half‑marathon snooze. Make the pause a defined interval—say 20‑30 seconds—then jump back to the target pace so you hit that lactate threshold zone. Run a test and log your cadence and HR; if the pause drops your cadence too low, shorten it or add a short sprint afterward to keep the adrenaline up. That way you get the “push‑and‑pause” effect without turning it into a nap. Good luck tweaking the percentages.