axisY

A number identifying which Y-axis to put the series on, when using multiple Y axes.
Defaults to 0, the first Y axis.

{
    axisY: [                    
        {
            title: {
                text: "Thinking Distance (m)",
                style: {
                    color: "#52B0F0"
                }
            }
        },
        {                  
            title: {
                text: "Braking Distance (m)",
                style: {
                    color: "#D7C43A"
                }
            }
        }
    ],
    dataSeries: [
        {
            axisY:0,
            collectionAlias: "Thinking Distance",
            data: [6, 9, 12, 15, 18, 21, 24]
        },
        {
            axisY: 1,
            collectionAlias: "Braking Distance",
            data: [6, 14, 24, 38, 54, 75, 96]
        }
    ]
}

This setting is demonstrated in the following example.