diff --git a/HillSet.js b/HillSet.js
index 02a935d..97c7e75 100644
--- a/HillSet.js
+++ b/HillSet.js
@@ -2,17 +2,18 @@
 
 class HillSet
 {
-	constructor(inSize, inHeightRange, inColour)
+	constructor(inSize, inHeightRange, inColour, inSpeed)
 	{
 		if(typeof inSize != "object") inSize = new Vector(2048, 1024);
 		if(typeof inHeightRange != "number") inHeightRange = 0.4;
 		if(typeof inColour != "string") inColour = "green";
+		if(typeof inSpeed != "number") inSpeed = 30;
 		
 		this.pos = new Vector(0, 0);
 		this.startPos = this.pos.clone();
 		this.size = inSize;
 		this.colour = inColour;
-		this.speed = 300; // in pixels per second
+		this.speed = inSpeed; // in pixels per second
 		
 		this.heightRangeMultiplier = inHeightRange;
 		this.heightRange = this.heightRangeMultiplier * this.size.y;
diff --git a/renderer.js b/renderer.js
index d9d07b0..09f8839 100644
--- a/renderer.js
+++ b/renderer.js
@@ -18,23 +18,23 @@ class Renderer
 	{
 		this.visibleObjects = [];
 		this.hillSets = [];
-		this.hillSets.push(new HillSet(new Vector(2048, this.canvas.height * 0.9), 0.4, "rgb(102, 164, 90)"));
-		this.hillSets.push(new HillSet(new Vector(2048, this.canvas.height * 0.6), 0.4, "rgb(43, 131, 35)"));
-		this.hillSets.push(new HillSet(new Vector(2048, this.canvas.height * 0.2), 0.4, "rgb(50, 111, 8)"));
+		this.hillSets.push(new HillSet(new Vector(2048, this.canvas.height * 0.9), 0.4, "rgb(102, 164, 90)", this.speed * 0.3));
+		this.hillSets.push(new HillSet(new Vector(2048, this.canvas.height * 0.6), 0.4, "rgb(43, 131, 35)", this.speed * 0.6));
+		this.hillSets.push(new HillSet(new Vector(2048, this.canvas.height * 0.2), 0.4, "rgb(50, 111, 8)", this.speed * 0.8));
+		this.visibleObjects.push(...this.hillSets);
+		
 		var hillOffset = this.canvas.height * 0.1;
 		this.hillSets[0].pos = new Vector(0, this.canvas.height - this.hillSets[0].size.y - hillOffset);
 		this.hillSets[1].pos = new Vector(0, this.canvas.height - this.hillSets[1].size.y - hillOffset);
 		this.hillSets[2].pos = new Vector(0, this.canvas.height - this.hillSets[2].size.y - hillOffset);
-		this.visibleObjects.push(...this.hillSets);
 		
 		this.road = new Road(this.canvas, new Vector(0, this.canvas.height * 0.9));
+		this.road.speed = this.speed;
 		this.visibleObjects.push(this.road);
 		
 		this.bicycle = new Bicycle(new Vector(this.canvas.width / 2, this.canvas.height * 0.9));
+		this.bicycle.speed = this.speed;
 		this.visibleObjects.push(this.bicycle);
-		
-		for (let vobj of this.visibleObjects)
-			vobj.speed = this.speed;
 	}
 	
 	start()