diff --git a/.gitignore b/.gitignore
index 136173f2eb..cf82c386a9 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,5 +5,6 @@
 editor/editor_state
 editor/road_edits.json
 editor/sim_state
+headless/sim_state
 data/*.abst
 data/input/*
diff --git a/headless/Cargo.toml b/headless/Cargo.toml
index cbca8bdbd1..cfc20207d9 100644
--- a/headless/Cargo.toml
+++ b/headless/Cargo.toml
@@ -4,6 +4,7 @@ version = "0.1.0"
 authors = ["Dustin Carlino <dabreegster@gmail.com>"]
 
 [dependencies]
+abstutil = { path = "../abstutil" }
 control = { path = "../control" }
 map_model = { path = "../map_model" }
 pretty_assertions = "0.5.1"
diff --git a/headless/src/main.rs b/headless/src/main.rs
index 4d120a354b..5ade5cbef9 100644
--- a/headless/src/main.rs
+++ b/headless/src/main.rs
@@ -1,5 +1,6 @@
 // Copyright 2018 Google LLC, licensed under http://www.apache.org/licenses/LICENSE-2.0
 
+extern crate abstutil;
 extern crate control;
 extern crate map_model;
 extern crate sim;
@@ -22,6 +23,14 @@ struct Flags {
     /// Use the old parametric sim
     #[structopt(long = "parametric_sim")]
     parametric_sim: bool,
+
+    /// Optional time to savestate
+    #[structopt(long = "save_at")]
+    save_at: Option<u32>,
+
+    /// Optional savestate to load
+    #[structopt(long = "load_from")]
+    load_from: Option<String>,
 }
 
 fn main() {
@@ -33,10 +42,16 @@ fn main() {
     // TODO could load savestate
     let control_map = control::ControlMap::new(&map);
     let mut sim = sim::Sim::new(&map, flags.rng_seed, flags.parametric_sim);
-    // TODO need a notion of scenarios
-    sim.seed_parked_cars(0.5);
-    sim.seed_pedestrians(&map, 100);
-    sim.start_many_parked_cars(&map, 100);
+
+    if let Some(path) = flags.load_from {
+        sim = abstutil::read_json(&path).expect("loading sim state failed");
+        println!("Loaded {}", path);
+    } else {
+        // TODO need a notion of scenarios
+        sim.seed_parked_cars(0.5);
+        sim.seed_pedestrians(&map, 100);
+        sim.start_many_parked_cars(&map, 100);
+    }
 
     let mut benchmark = sim.start_benchmark();
     loop {
@@ -45,5 +60,11 @@ fn main() {
             let speed = sim.measure_speed(&mut benchmark);
             println!("{0}, speed = {1:.2}x", sim.summary(), speed);
         }
+        if let Some(ticks) = flags.save_at {
+            if sim.time == sim::Tick::from_raw(ticks) {
+                abstutil::write_json("sim_state", &sim).expect("Writing sim state failed");
+                println!("Wrote sim_state at {}", sim.time);
+            }
+        }
     }
 }
diff --git a/sim/src/lib.rs b/sim/src/lib.rs
index 4098dfdcb1..ad1d15fb89 100644
--- a/sim/src/lib.rs
+++ b/sim/src/lib.rs
@@ -81,6 +81,10 @@ impl Tick {
         Tick(0)
     }
 
+    pub fn from_raw(ticks: u32) -> Tick {
+        Tick(ticks)
+    }
+
     pub fn as_time(&self) -> Time {
         (self.0 as f64) * TIMESTEP
     }